Resource USUM UU Cores

[Accel]

Co-hosted by Amaroq
Shoutouts to Euphonos and Amaroq for most of the original OP, as well as dodmen and Calloflochie for hosting last generation's thread.
Approved by Kink and Hogg

Welcome to the USUM edition of the UU Cores thread! The purpose of this thread is for the community to post and discuss various cores that work well in the metagame.


As you all know, a core is a group of usually 2 or 3 Pokemon in the team that work together toward a specific goal. These goals include breaking through opposing teams (Offensive), covering each other's weaknesses while providing the team with a solid set of resistances (Defensive), and checking important threats in the UU metagame while exerting offensive pressure upon the opposing team (Balanced).


All cores are welcome in this thread, as long as they meet the following guidelines:

1. Cores posted here must be tested to ensure that they perform well in the metagame. Therefore, including replays is recommended to further support the validity of your core. Try to keep slashes to a minimum.
   
   
2. Include a short, concise description or explanation of the core, which should contain the following information:

• How the core functions
• How to use the core itself

Please follow the following format when presenting a core:

1. Provide the sprites and names of the Pokemon that make up your core.

2. Include the sets for your Pokemon (preferably in hide tags).

3. Write up a short description of how the core functions.


Here's an example of what a proper submission should look like:

Example

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Sets

Rotom-Wash @ Leftovers
Ability: Levitate
EVs: 248 HP / 84 Def / 176 Spe
Bold Nature
IVs: 0 Atk
- Will-O-Wisp
- Pain Split
- Hydro Pump
- Volt Switch

Scizor @ Fightinium Z
Ability: Technician
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Swords Dance
- Bullet Punch
- U-turn
- Superpower

The combination of Rotom-W and Scizor may be a generic pairing, but it is also one that has procured steady results for many offensive and balance teams from and following the BW era. Rotom-W acts as a general pivot here, checking the vast majority of physically offensive Pokemon by virtue of Will-O-Wisp. It also provides a decent Fire resist and the option to keep up the pace of the game through Volt Switch, both of which complement Scizor. SD + 3 attacks is also a very standard set, and with Fightinium Z, Scizor can function as both a wallbreaker and cleaner, while checking the Grass and Dragon types that Rotom-W may not be able to handle. Basically, this core is a tried-and-true base for many teams and significantly eases the potential strain teambuilding can have, even to this day.

USUM CORES ARCHIVE

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Offensive Cores

+(Sceptile-Mega + Scarf Infernape) by ACakeWearingAHat
+(DD Altaria-Mega + Specs Magneton) by ACakeWearingAHat
+(LO Mixed Infernape + Scarf Latias) by Amaroq
+(Band Scizor + Scarf Hydreigon) by SuperVegeta20
++(SubSeed Serperior + Flynium Z Talonflame + Band Azumarill) by TSR
+(Nasty Plot Salazzle + Serperior) by Wascally Wabbit
+(Stakataka + Trapper Azumarill) by warzoid
++(Mega Beedrill + Mamoswine + Magneton) by warzoid
+(Stakataka + Primarina) by ACakeWearingAHat
+(SD Breloom + AV Alolan Muk) by Hilomilo

Balanced Cores

+(AV Muk-Alola + SubSeed Serperior) by Amaroq
++(Mixed Wall Hippowdon + Band Stoutland + Aerodactyl-Mega) by Amaroq
+(AV Muk-Alola + Specs Volcanion) by Amane Misa
+(Seismitoad + Work Up Stallbreaker Pidgeot) by yeezyknows
+(Support Gliscor + Band Scizor) by Sacri'
++(Scarf Hydreigon + Amoonguss + Rotom-Heat) by warzoid

Defensive Cores

++(Blissey + Alomomola + Quagsire) by Amane Misa

+(Sylveon + Mega Aggron) by SuperVegeta20
++(Gastrodon + Mega Aggron + Sylveon) by warzoid

Outdated Cores

Outdated Cores

+(Physically Defensive Rotom-W + Band Scizor) by Amane Misa
+(Firium-Z Ninetales + LO Venusaur) by Darksafadao

 

[A Cake Wearing A Hat]

Importable

Sceptile-Mega @ Sceptilite
Ability: Lightning Rod
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Leaf Storm
- Dragon Pulse
- Giga Drain
- Hidden Power [Fire]

Infernape @ Choice Scarf
Ability: Blaze
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Flare Blitz
- Close Combat
- U-turn
- Gunk Shot / Stone Edge

This offensive core is built around Mega Sceptile slapping opposing Water-types and Dragon-types like Rotom-W, Swampert, and Latias that Infernape struggles with and Infernape pressuring Steel-types like Scizor, Grass-types like Celebi and Amoonguss, and faster threats like Mega Aerodactyl and Choice Scarf Hydreigon. Infernape also gives more opportunities for Mega Sceptile to come in thanks to U-turn. Overall this core is pretty easy to use and pairs well with other VoltTurn users or Spikes support.

Importable

Altaria-Mega @ Altarianite
Ability: Pixilate
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Dragon Dance
- Facade
- Earthquake
- Roost

Magneton @ Choice Specs
Ability: Magnet Pull
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Thunderbolt
- Flash Cannon
- Volt Switch
- Hidden Power [Fire]

Another neat offensive core which is based around Magneton trapping troublesome Steel-types like Scizor, weakened Mega Aggron, and Magnet Rise Klefki, and then having Mega Altaria clean up with your personal preference of Dragon Dance set (I run Adamant Facade because Altaria attracts opposing status effects like flies to honey, it lets you run Earthquake without worrying about opposing status inducers like Rotom-W, and it also just hits ridiculously hard when statused.)

 

[Amaroq]

Sets

Muk-Alola @ Assault Vest
Ability: Poison Touch
EVs: 248 HP / 112 Atk / 148 SpD
Careful Nature
- Knock Off
- Pursuit
- Poison Jab
- Fire Punch

Serperior @ Leftovers
Ability: Contrary
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Substitute
- Leech Seed
- Leaf Storm
- Hidden Power [Fire]

Serperior was recently unbanned and has proven itself a notable threat in the tier, but it still struggles with a decent number of Pokemon in UU: Dragon-types, Moltres, etc. Muk-Alola can come in on Pokemon like Latias and trap them, paving the way for Serperior to spam Leaf Storm. In return, Serperior can pressure stall with Substitute + Leech Seed and use Leech Seed to keep Muk-Alola healthy. Residual damage from Poison Touch and Leech Seed helps this core wear down teams. The Muk-Alola spread is something I came up with a while ago to stop Modest Primarina from 2HKOing with Hydro Pump after Stealth Rock, but a more generic spread works just fine. Seismitoad and Rotom-W make good partners for this core, as both appreciate Muk-Alola's ability to remove Latias, can check Mega Aerodactyl, and benefit from Leech Seed recovery. Seismitoed can set up Stealth Rock and serve as a hard stop to VoltTurn, while Rotom-W provides pivot support to help Serperior and Muk-Alola switch in safely and can use Defog to clear hazards.

Sets

Infernape @ Life Orb
Ability: Blaze
EVs: 168 Atk / 88 SpA / 252 Spe
Naive Nature
- Overheat
- Close Combat
- Grass Knot
- Gunk Shot

Latias @ Choice Scarf
Ability: Levitate
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Draco Meteor
- Psychic
- Hidden Power [Fire]
- Healing Wish

Mixed Infernape is a nice breaker that can put in a lot of work vs. bulkier teams, but doesn't have as much of an impact vs. offense. Choice Scarf Latias does well against offense, but struggles to seriously threaten bulkier Pokemon. Infernape breaks down walls and removes Steel-types for Latias, while Latias revenge kills faster Pokemon that threaten Infernape. In addition, they have decent typing synergy (Infernape resists the Ice-, Dark-, and Bug-type attacks that Latias is weak to, while Latias covers Psychic-, Water-, and Ground-type attacks for Infernape). Finally, stall has enough trouble dealing with mixed Infernape the first time around, and Healing Wish allows it a second chance at breaking and enables the user to be aggressive with Infernape. Latias can run any number of moves in the third slot, such as Defog, Trick, or a coverage move, depending on team composition.

Sets

Hippowdon @ Leftovers
Ability: Sand Stream
EVs: 240 HP / 76 Def / 192 SpD
Impish Nature
- Stealth Rock
- Earthquake
- Slack Off
- Toxic / Whirlwind

Stoutland @ Choice Band
Ability: Sand Rush
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Return
- Superpower
- Crunch
- Facade / Pursuit

Aerodactyl-Mega @ Aerodactylite
Ability: Tough Claws
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Stone Edge
- Wing Attack
- Earthquake
- Pursuit / Aqua Tail

Hippowdon + Stoutland + Mega Aerodactyl is the standard sand core. Hippowdon sets up sand and serves as a general purpose wall, providing additional utility through Stealth Rock and either Toxic or Whirlwind. Stoutland provides the team with a breaker or cleaner, depending on matchup, outspeeding anything slower than Choice Scarf users with base 108 Speed under sand and still hitting hard with base 110 Attack and a Choice Band. The choice between Pursuit and Facade depends on whether the player wants Stoutland to function when afflicted with status or trap the frail, offensive Pokemon it threatens out under sand. Aerodactyl provides additional, more reliable speed control and has surprising special bulk in sand. Pursuit is nice for trapping purposes, but Aqua Tail allows Mega Aerodactyl to hit Pokemon like Gliscor and Hippowdon super effectively. Aqua Tail can also replace another coverage move, depending on what the team needs. Mega Aerodactyl can also take advantage of the additional bulk sand confers to set up with Hone Claws and threaten to sweep. Good teammates can check the Water-types that this core struggles with or provide other utility options that teams normally value (Defog, Taunt, cleric support, etc) and include Pokemon like Latias, Rotom-W, Serperior, Klefki, Scizor, Tentacruel, Sylveon, and Empoleon. Reuniclus also makes a good teammate, as Magic Guard makes it immune to sand damage. I've expanded a bit more on how to play sand and use the specific Pokemon in this core here.

 

[vivalospride]

Importable

Scizor (M) @ Choice Band
Ability: Technician
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Bullet Punch
- U-turn
- Superpower
- Pursuit

Hydreigon (M) @ Choice Scarf
Ability: Levitate
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Dark Pulse
- Draco Meteor
- Fire Blast
- U-turn

Even though Volt Turn isn’t quite as broken as it was pre USUM, it is still in a good spot. This core is a little U-Turn core with Scizor and Hydreigon, two of the best choice users in the tier. Hydreigon can be used as a fire resist, is one of the best scarfers in the tier, has hard hitting stab and U-Turn, while Scizor is one of the best band users in the tier, has U-Turn, priority to make up for its poor speed, and Pursuit. This core is pretty standard on Volt Turn teams and is pretty easy to use and put dents into the enemy team and let your wincon clean up.

 

[TSR]

Let's just pray Serperior and Azumarill don't get banned for some absurd reason and render this post obsolete

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Sets

Talonflame @ Flyinium Z
Ability: Gale Wings
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Swords Dance
- Flare Blitz
- Brave Bird
- Roost

Serperior @ Leftovers
Ability: Contrary
EVs: 56 HP / 200 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Substitute
- Leaf Storm
- Hidden Power [Fire]
- Leech Seed

Azumarill @ Choice Band
Ability: Huge Power
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Liquidation
- Play Rough
- Knock Off / Superpower / Ice Punch
- Aqua Jet

I've personally been trying to get various things to work in the last week and I've come to like this offensive core a lot. Talonflame + Serperior + Azumarill is an solid core dating back to the days of XY OU, but with the introduction of Z-moves and USUM move tutors they come with a couple new tricks up their sleeve. Talonflame on its own can be a nightmare for offensive teams lacking Rotom-Wash, Mega Manectric, or Mega Aerodactyl as it is deceptively hard to stop it from setting up against the right Pokemon, and many other threats like Latias and Primarina would much rather not be on the receiving end of +2 Supersonic Skystrike. Talonflame baits in bulky Water-types, Rock-types, or generally bulky physical walls like Swampert, Suicune, and Hippowdon which Serperior loves to come in and get subs on and proceed to throw Leech Seed and Leaf Storm around. Serperior can run a Defogging set if role compression is required, as reliable hazard control is mandatory with the use of Talonflame. Azumarill completes the core by providing a strong physical wallbreaker that can bust up some defensive threats like Swampert and Alomomola to clear the way for a Talonflame sweep. It can also run Ice Punch in the slot where you'd normally see Knock Off or Superpower to pressure Amoonguss for Serperior. A hyper offensive core such as this also comes with two forms of priority as well which is never too shabby. Obviously this three mon core is pretty dedicated to supporting each other only on the offensive spectrum, so it may sometimes struggle with the standard lineup of offense killers like Mega Beedrill, Mega Aerodactyl, Crobat, Latias, and Mega Manectric so some teammates such as Mega Steelix, Hippowdon (just don't run Sand Stream + gen 7 Gale Wings lol), Alolan Muk, Suicune, Togekiss, Sylveon, and Rotom-Wash can potentially create an effective defensive backbone for the team.

 

[Amane Misa]

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Description

Alomomola + Blissey wall a large portion of the metagame themselves, with Alomomola being able to take on the majority of physical attackers and with Blissey being able to take on the majority of special attackers. However, set-up sweepers can boost themselves in order to overpower both Alomomola and Blissey; this is where Quagsire comes. Thanks to Unaware, Quagsire is able to take on sweepers, such as Cobalion and Scizor, who may otherwise overpower Alomomola and Blissey.

Sets

Alomomola @ Leftovers
Ability: Regenerator
EVs: 168 HP / 252 Def / 88 SpD
Bold Nature
- Wish
- Protect
- Scald
- Toxic

Blissey @ Leftovers
Ability: Natural Cure
EVs: 248 HP / 252 Def / 8 SpD
Bold Nature
IVs: 0 Atk
- Stealth Rock
- Seismic Toss
- Toxic
- Soft-Boiled

Quagsire @ Leftovers
Ability: Unaware
EVs: 252 HP / 244 Def / 12 Spe
Impish Nature
- Toxic / Curse
- Scald
- Earthquake
- Recover

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Description

A pretty common and effective VoltTurn core. Rotom-W is able to threaten Scizor's common switch-ins, mainly as bulky Steel- and Ground-types, and Scizor is able to threaten Rotom-W's common switch-ins, mainly bulky Grass- and Dragon-types. Rotom-W can also cripple Scizor's checks with status and Scizor can also Pursuit trap some of Rotom-W's checks.

Sets

Rotom-Wash @ Leftovers
Ability: Levitate
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
IVs: 0 Atk / 30 Spe
- Volt Switch
- Hydro Pump
- Toxic / Will-O-Wisp / Defog
- Pain Split

Scizor @ Choice Band
Ability: Technician
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Bullet Punch
- U-turn
- Superpower
- Knock Off / Pursuit / Bug Bite

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Description

Volcanion is proving itself to be a force to be reckoned with, boasting powerful STABs, great power, and coverage. Even resists, such as Rotom-W, are often 2HKO'd by Volcanion's STABs. However, Volcanion still struggles against bulkier resists, such as Latias and against Special walls, such as Blissey. Alolan Muk reliably beats all the aforementioned Pokémon and even threatens them with Pursuit, so they can't switch out against it freely.

Sets

Volcanion @ Choice Specs
Ability: Water Absorb
EVs: 252 SpA / 4 SpD / 252 Spe
Modest / Timid Nature
IVs: 0 Atk
- Steam Eruption
- Fire Blast
- Sludge Bomb
- Earth Power / Hidden Power Grass

Muk-Alola @ Assault Vest
Ability: Poison Touch
EVs: 204 Atk / 180 SpD / 124 Spe
Adamant / Brave Nature
- Pursuit
- Knock Off
- Gunk Shot / Poison Jab
- Fire Punch / Fire Blast

 

[yeezyknows]

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yo so what switches into work up m-pidge? maero, mane, and rotom-w do. what counters these 3 mons while tossing up those qt3.14159265 rocks? ur boy seis does. how many switch-ins do mane and maero have after rocks are put up? one. how much does +1 cane do to physdef washtom?

a p fair amount: +1 252 SpA Pidgeot-Mega Hurricane vs. 248 HP / 0 SpD Rotom-Wash: 131-154 (43.2 - 50.8%) -- 53.1% chance to 2HKO after Stealth Rock and Leftovers recovery

meaning that if homie's washtom has iapapa or even a lil chip, it's not coming in safely.

simply put, you can start by leading w m-pidge. if they have one of those 3 mons, you go seis on the switch, get up your qt3.14 rocks, throw off a toxic or double, sit back, and wait for openings to put qt3.14 birdy back in the game. its that ez

m-pidge been disrespected ever since washtom dropped and now it's time to show birdy some love. play with this core. beat offense, beat balance, beat stall. win games.

SETS

Seismitoad @ Leftovers
Ability: Water Absorb
EVs: 252 HP / 252 Def / 4 SpD
Relaxed Nature
- Scald
- Stealth Rock
- Toxic
- Earthquake/Knock Off

Pidgeot-Mega @ Pidgeotite
Ability: No Guard
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Hurricane
- Work Up
- Refresh
- Roost

 

[pokemonisfun]

+

yo so what switches into work up m-pidge? maero, mane, and rotom-w do. what counters these 3 mons while tossing up those qt3.14159265 rocks? ur boy seis does. how many switch-ins do mane and maero have after rocks are put up? one. how much does +1 cane do to physdef washtom?

a p fair amount: +1 252 SpA Pidgeot-Mega Hurricane vs. 248 HP / 0 SpD Rotom-Wash: 131-154 (43.2 - 50.8%) -- 53.1% chance to 2HKO after Stealth Rock and Leftovers recovery

meaning that if homie's washtom has iapapa or even a lil chip, it's not coming in safely.

simply put, you can start by leading w m-pidge. if they have one of those 3 mons, you go seis on the switch, get up your qt3.14 rocks, throw off a toxic or double, sit back, and wait for openings to put qt3.14 birdy back in the game. its that ez

m-pidge been disrespected ever since washtom dropped and now it's time to show birdy some love. play with this core. beat offense, beat balance, beat stall. win games.

SETS

Seismitoad @ Leftovers
Ability: Water Absorb
EVs: 252 HP / 252 Def / 4 SpD
Relaxed Nature
- Scald
- Stealth Rock
- Toxic
- Earthquake/Knock Off

Pidgeot-Mega @ Pidgeotite
Ability: No Guard
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Hurricane
- Work Up
- Refresh
- Roost

Let me just say this is a great core. And in my experience, it works just as well and even more logically with a standard U-Turn Pidgeot set. Against teams with Rotom Wash, you have an amazing matchup since Rotom Wash is usually their switch in to Pidgeot but you can just safely U-Turn 100% of the time when they come in for free momentum or SR as Seismitoad completely blocks Rotom.

The same principle also works with Crobat since Crobat also gets annoyed by Rotom. Synergy is really good in this core.

 

[Sacri']

sets

Gliscor @ Toxic Orb
Ability: Poison Heal
EVs: 244 HP / 204 SpD / 60 Spe
Careful Nature
- Stealth Rock
- Toxic
- Roost
- Earthquake

Scizor @ Choice Band
Ability: Technician
EVs: 252 HP / 252 Atk / 4 Def
Adamant Nature
- U-turn
- Pursuit
- Superpower
- Bullet Punch

A fun core I've been messing with. Spedef Gliscor is great at weakening waters type for Scizor's bp whereas Scizor can threaten more offensive mons thanks to the strongest priority in the tier. For instace, Gliscor can lure Defensive Rotom into thinking it can get an easy defog ogg but it actually has enough spedef to beat it 1v1 while still getting rocks up. I run full hp on Scizor because it allows it has an easier time checking things like Latias and Aerodactyl. You could run taunt on Gliscor if you already have a rockers and use taunt to annoy defensive 'mons even more.

 

[vivalospride]

Sylveon + Mega Aggron

Sets

Sylveon @ Leftovers
Ability: Pixilate
EVs: 252 HP / 252 Def / 4 Spe
Bold Nature
IVs: 0 Atk
- Wish
- Protect
- Hyper Voice
- Heal Bell

Aggron-Mega (M) @ Aggronite
Ability: Filter
EVs: 252 HP / 4 Def / 252 SpD
Careful Nature
- Stealth Rock
- Roar
- Heavy Slam
- Earthquake / Fire Punch

So yeah I've been using this core a lot and so have a lot of other people and I think it is one of the better cores rn especially because of how prominent fat teams are in the meta rn due to Steakhouse dropping to UU. This core is great on fatter teams, these two pokemon's typings compliment each other greatly and wish support greatly helps Mega Aggron to consistently check things such as the steakhouse. I personally like EQ > Fire Punch rn just because of stakakakakakaka, but Fire Punch is still great because of Scizor being the most common mon in the tier by miles. Yeah this core is super fun to use and play, good luck UUsers :D.

 

[Darksafadao]

Hi, I would like to share a core I've been testing for a while.

sets

Ninetales @ Firium Z
Ability: Drought
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Nasty Plot
- Fire Blast
- Solar Beam
- Hypnosis


Venusaur @ Life Orb
Ability: Chlorophyll
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Sludge Bomb
- Giga Drain
- Hidden Power [Fire]
- Growth

Yeah, I know this core seem pretty straight forward, but I wanna comment on how it is a bit more complex than it may look at first. The most crucial point: Ninetales' Drought activates Venusaur's Chlorophyll, making it a potential cleaner. But not only that, Ninetales is actually a really nice wallbreaker with Firium Z and Nasty Plot, and the usual walls that would try to stop Ninetales are the ones that usually stop Venusaur, such as Blissey and Tentacruel, weakning/killing them for Venusaur. Ninetales' drought also boosts growth and helps Venusaur set up even more easily on water-types. Taking advantage of its high speed, Ninetales usually has two opportunities to land a Hypnosis on a predicted switch, making Venusaur's job easier. With this I wanna say this core isn't only about a sun setter and a sun abuser core, but also about a wallbreaker and a cleaner. (I chose a timid nature on Venusaur to outspeed common scarfers such as Infernape and Latias, but modest probably works as well).
Thanks for reading.

 

[YABO]

Just run Heat Rock on Tales and Poisinium Z on Venusaur, it's way more consistent.

 

[Parkzy]

DEFENSIVE CORE
This is in incredibly hard to break defensive core consisting of some UU favourites. You probably know how this core works and you should! This core is a very easy to use core but always really forces the opponent into un-wantable situations. First lets start with Magneton. I personally use specs to help Muk-Alola pick up Koes with pursuit but honestly scarf works well as well. Magneton with hp fire and a great sp.atk can really fire off super strong stab attacks and with a good double you can trap the annoying steels which are the bane to Latias and A-Muk. Magneton is just incredible. 11 resistances and 1 immunity with only three moves super effective against it which Latias sponges. Next, Muk-Alola. With the recent drops Gengar fell to UU and Muk-Alola is the best switch in. Most likely paired alongside this core A-Muk is best AV and can chip teams down with 51% poison poison jabs and knock offs it can really set the path for your sweepers. Finally Latias the best defogger in UU and alongside Magneton and A-Muk can run crazy with a good variety of sets like scarf, soul dew or specs. But I prefer colbur berry two attacks roost and defog. Latias helps cover the other twos ground weaknesses, only haxorus can break through this core and it needs dragon stab and eq with a dragon dance up. As for mons to pair well with this core Azumarill, Infernape, Serperior or any good wallbreaker/set up sweeper in the format.

Magneton @ Choice Specs/Choice Scarf
Ability: Magnet Pull
Shiny: Yes
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Volt Switch
- Thunderbolt
- Flash Cannon
- Hidden Power [Fire]

Latias @ Colbur Berry
Ability: Levitate
EVs: 252 HP / 252 SpD / 4 Spe
Calm Nature
IVs: 0 Atk
- Defog
- Recover
- Ice Beam
- Thunderbolt

Ivan Ooze (Muk-Alola) @ Assault Vest
Ability: Poison Touch
EVs: 252 HP / 252 Atk / 4 SpD
Adamant Nature
- Knock Off
- Poison Jab
- Pursuit
- Shadow Sneak

 

[billionbattler]

MBee + Scarf Magneton + Band Azu

Sets for this great core

Beedrill-Mega @ Beedrillite
Ability: Adaptability
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Drill Run
- Pursuit
- Poison Jab
- U-turn

Magneton @ Choice Scarf
Ability: Magnet Pull
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Flash Cannon
- Hidden Power [Fire]
- Thunderbolt
- Volt Switch

Azumarill @ Choice Band
Ability: Huge Power
EVs: 64 HP / 252 Atk / 192 Spe
Adamant Nature
- Aqua Jet
- Ice Punch
- Liquidation
- Play Rough

This may seem like an odd VoltTurn core + an attacker that likes being pivoted in but ive played with this pre-usum but it got even better with azu being unbanned. The way this core works is like any VoltTurn core would but i put pursuit over knock off on mbee for threats like latias that magneton cant really touch. The core was weak to fire and fighting so i put azu on there to cover those weaknesses and also likes being pivoted in.
Magneton also could run specs but i liek scarf better for more speed control.
I also have the generic Scizor and a fire check core although i took a bulkier approach to it

Sets for this core

Scizor @ Leftovers
Ability: Technician
EVs: 248 HP / 124 Def / 136 SpD
Careful Nature
- Bullet Punch
- U-turn
- Swords Dance
- Roost

Snorlax @ Figy Berry
Ability: Thick Fat
EVs: 188 HP / 252 Def / 68 SpD
Impish Nature
- Curse
- Earthquake
- Facade
- Recycle

Scizor + a fire check is very generic but effective although this one is a bulkier one with bulky sd scizor and recycle curse lax. This core is pretty fat and works on BO and balance archetypes or possibly semistall. Snorlax with thicc fat helps it better check and remove fire types for scizor. Snorlax can also beat nape but only after a few curse boosts prior to the nape switch in. Scizor semi covers snorlax's fighting weakness and banded scizor or fight z scizor would also work to better cover steel types since only snorlax's eq hits steel types for SE damage.

 

[justdrew]

Salazzle @ Firium Z
Ability: Oblivious
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Nasty Plot
- Fire Blast
- Sludge Wave
- Hidden Power [Grass]

Serperior @ Meadow Plate
Ability: Contrary
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Leaf Storm
- Hidden Power [Fire]
- Giga Drain
- Dragon Pulse/Defog

Now I know at first glance you see Salazzle and are thinking that it's an Unmon and this core should be disregarded. But take a closer look. This Pokemon outspeeds Serperior and Latias two of the most used Pokemon in the UU tier, and at the same time resists Scizors Bullet Punch making it even more useful versus the current UU meta. The stall breaking abilities of Salazzle and Serperior combined are amazing. Salazzle is great versus pretty much every Pokemon as it's moveset allows for it to hit every Pokemon super effectively or neutrally, no resistances. Serperior helps Salazzle against bulky Water types that threaten it while Salazzle helps Serperior break through special walls like Blissey and Alo-Muk.

 

[warzoid]

Balanced Core: Hydreigon + Amoonguss + Rotom-Heat

Sets

Hydreigon @ Choice Scarf
Ability: Levitate
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
- Draco Meteor
- Dark Pulse
- Fire Blast
- U-turn

Amoonguss @ Black Sludge
Ability: Regenerator
EVs: 252 HP / 184 Def / 72 SpD
Sassy Nature
IVs: 0 Atk / 0 Spe
- Spore
- Giga Drain
- Clear Smog
- Hidden Power [Fire]

Rotom-Heat @ Firium Z
Ability: Levitate
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Overheat
- Volt Switch
- Pain Split
- Defog

Hydreigon gives opposing fairies such as Azumarill and Mega Altaria a free switch, so Amoonguss is a natural partner. Amoonguss also absorbs fighting attacks aimed at Hydreigon and water attacks aimed at Rotom-Heat. Hydreigon can switch into psychic and fire type attacks for Amoonguss. Rotom-Heat covers weaknesses to ice types such as Mamoswine and flying types such as Mega Pidgeot. It also forms a nice VoltTurn core with Hydreigon. The sets aren't too crucial to the core's synergy; you could easily run a Roost Hydreigon and choiced Rotom-Heat if you wished. Partner this core up with a Mega Aero check and something that can sponge Draco Meteors.

Offensive Core: Stakataka + Perish Trapper Azumarill

Sets

Stakataka @ Rockium Z
Ability: Beast Boost
EVs: 252 HP / 252 Atk / 4 SpD
Lonely Nature
IVs: 15 Def / 0 Spe
- Gyro Ball
- Stone Edge
- Earthquake
- Trick Room

Azumarill @ Leftovers
Ability: Sap Sipper
EVs: 252 HP / 252 Def / 4 SpD
Impish Nature
- Whirlpool
- Perish Song
- Protect
- Play Rough

Stakataka struggles with fat walls like Amoonguss and Alomomola. They also happen to be common Azumarill switchins. Trapper Azumarill can lure out and eliminate those annoying walls, allowing OTR Stakataka to do its thing. If Azumarill is running Play Rough, it also checks many variants of Bulletproof Kommo-o, another problem mon for Stakataka.

Some room tour replays showcasing the first 2 cores:

Replays

Azumarill weakens Scizor and Stakataka cleans
Rotom-Heat checks a Mamoswine
more Rotom-Heat action + Celebi gets trapped
I misplay Staka but the Drei/Heat/Shroom core does work

Offensive Core: Mega Beedrill + Magneton + Mamoswine

Sets

Beedrill-Mega @ Beedrillite
Ability: Swarm
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- U-turn
- Poison Jab
- Drill Run
- Toxic Spikes

Magneton @ Choice Scarf
Ability: Magnet Pull
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Thunderbolt
- Volt Switch
- Flash Cannon
- Hidden Power [Fire]

Mamoswine @ Life Orb
Ability: Thick Fat
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Earthquake
- Ice Shard
- Icicle Crash
- Stealth Rock

Beedrill and Mamoswine hate Scizor. Enter Magneton. Magneton and Beedrill hate Gliscor. Enter Mamoswine. Beedrill hates Crobat. Enter . . . you get the idea. Add some teammates that can check Stakataka, Rock Polish Cobalion, and scarf Infernape. I have only one short replay of the core in action, but you can see the synergy as having Magneton in the back hinders the opposing Scizor's ability to deal with Beedrill and Mamoswine.

Defensive Core: Gastrodon + Mega Aggron + Syvleon

Sets

Gastrodon @ Leftovers
Ability: Storm Drain
EVs: 252 HP / 164 Def / 92 SpD
Calm Nature
IVs: 0 Atk / 14 Spe
- Scald
- Ice Beam
- Toxic
- Recover

Aggron-Mega @ Aggronite
Ability: Sturdy
EVs: 252 HP / 16 Def / 240 SpD
Impish Nature
- Stealth Rock
- Heavy Slam
- Fire Punch
- Dragon Tail

Sylveon @ Leftovers
Ability: Pixilate
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
IVs: 0 Atk
- Wish
- Protect
- Hyper Voice
- Heal Bell

I know someone already posted the Aggron + Sylveon core, but Gastrodon can really shine when partnered up with them to form a water-fairy-steel core. Gastrodon resists fire type attacks for Aggron and Sylveon and soaks up any Scalds that might come Aggron's way. It also stops electric types from spamming Volt Switch, since most of them run Hidden Power Ice for Gliscor. A specially defensive spread lets it counter dangerous wallbreakers such as Nidoking and Gengar. Gastrodon can run additional special defense to check Primarina and more reliably deal with Nidoking, although additional physical defense can help with physical fire types such as Darmanitan and scarf Infernape. Christo's team from SPL week 2 is a good example of how to use this core.

 

[A Cake Wearing A Hat]

sets

Stakataka @ Rockium Z
Ability: Beast Boost
EVs: 252 HP / 252 Atk / 4 SpD
Lonely Nature
IVs: 15 Def / 0 Spe
- Stone Edge
- Trick Room
- Gyro Ball
- Earthquake

Primarina @ Choice Specs
Ability: Torrent
EVs: 4 Def / 252 SpA / 252 Spe
Modest Nature
IVs: 0 Atk
- Moonblast
- Hydro Pump
- Psychic
- Sparkling Aria

This bulky offense core takes advantage of Primarina's role as a special wallbreaker and ability to pressure Ground- and Fighting-types that trouble Stakataka, while Stakataka softens up offensive teams, sets Trick Room to assist Primarina in doing the same, and makes for a fine cleaner. Nothing else to it, really.

 

[Hilomilo]

Offensive Core: Breloom + Alolan Muk

sets

Breloom @ Life Orb
Ability: Technician
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Bullet Seed
- Mach Punch
- Swords Dance
- Spore / Rock Tomb

Muk-Alola @ Assault Vest
Ability: Poison Touch
EVs: 204 Atk / 180 SpD / 124 Spe
Adamant Nature
- Pursuit
- Knock Off
- Gunk Shot / Poison Jab
- Fire Punch

This is a core I've been enjoying using a lot since Breloom's been playable. With the given set Breloom is going to look to function as a sweeper, and Alolan Muk is going to do a really nice job supporting it. Some of the largest obstacles for Breloom are fast specially offensive Fighting-resists, most notably Latias, Gengar, Celebi, Starmie, and Chandelure. All of these threats are pretty adequately covered by Alolan Muk, which can allow Breloom to more easily work towards cleaning up in the late-game. This core does have a few struggles, one being its particular susceptibility to Infernape, so pairing it with a bulkier offensive Water- or Ground-type like Azu or Gliscor is never a bad idea. Breloom's set can also be adjusted (i.e. Ganlon Berry natural gift for Amoonguss and Mega Altaria in 4th slot) depending on how you wish to construct the rest of your team. Overall a great core with great synergy that I hope you guys try out, I've liked it a lot so far :)

 

[yeezyknows]

Gonna try to revive this thread with a cool defensive core for balance/bo builds. Sap sipper azu is an incredibly versatile mon rn, it works really well on balance because it hard checks/counters techniloom and serp, can break stall well, and can pivot into hydreigon pretty freely. Rhy's also rose to prominence recently since it fits into this meta super well. Provides rocks, an elec immunity, a flying resist, and a fire resist while not being passive. The two cover their weaknesses almost perfectly, with rhy switching in on poison/electric, and azu switching in on water, grass, ice, and fighting. If you've been having probs with loom/stall and want to try out rhyperior, feel free to give it a shot.

+

Hide

Azumarill @ Leftovers
Ability: Sap Sipper
EVs: 252 HP / 236 Def / 20 SpD
Bold Nature
IVs: 0 Atk
- Whirlpool
- Perish Song
- Protect
- Rest

Rhyperior @ Leftovers
Ability: Solid Rock
EVs: 252 HP / 4 Atk / 252 SpD
Careful Nature
- Stealth Rock
- Ice Punch
- Earthquake
- Stone Edge

 

[Mellow]

Just to note, the archive has a couple of outdated cores due to Mamoswine and Amoonguss moving out of the tier.

 

[pkfire.exe]

Infernape @ Firium Z
Ability: Blaze
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Fire Blast
- Grass Knot
- Nasty Plot
- Vacuum Wave

Muk-Alola @ Assault Vest
Ability: Poison Touch
EVs: 132 HP / 252 Atk / 124 Spe
Adamant Nature
- Poison Jab
- Knock Off
- Pursuit
- Fire Punch

Scizor @ Choice Band
Ability: Swarm
EVs: 80 HP / 252 Atk / 176 Spe
Adamant Nature
- U-turn
- Bullet Punch
- Knock Off
- Superpower

this is a core i've been using for a while now, and i thought i would share it here.
alolan muk is really handy for infernape in that because it deals with a lot of theats infernape hates to deal with, like starmie, latias, and chandelure. it can trap all of these nicely while being able to sponge their attacks easily with av, and spamming knock off early game eases inferenape's late game sweep. i noticed infernape and alolan muk are both fairly weak to mega aero, so i brought in scizor, which can take care of it fairly well, and can do really nice chip damage with u turn, while also being able to safely bring in alolan muk to trap/dispose targets like mega sceptile. . now, enter infernape, the late game sweeper. after the opposing team is weakened, infernape becomes a really handy sweeper, as it does really good once checks are eliminated, and the other team is weakened, but that does not mean it can't do serious damage early game if needed, however, as its' typing lets it force out switches on mons like scizor, where it can then get a free nasty plot boost.