First time teambuilder looking for advice

[Cadoo29]

Hello guys, I'm new to competitive Pokemon battling and after trying out some teams I wanted to give it a shot at creating a team myself. I started with wanting to create a team centered around Rillaboom . I did some research and I found that and made for a solid offensive core to begin my team building process. I've experimented with a lot of different mons and some different sets and I would like some suggestions or advice on what pokemon could round out this team better. I'm open to any suggestions whether it be changing mons/sets/teras, but I would like to keep the Rillaboom/Sneasler core. This is what I have been running currently.

Rillaboom @ Choice Band
Ability: Grassy Surge
Tera Type: Fairy
EVs: 252 Atk / 4 Def / 252 Spe
Adamant Nature
- Wood Hammer
- U-turn
- Knock Off
- Drain Punch

Rillaboom is the main component of the team I am trying to build around. The main idea with this set is that he sets up grassy surge and then hits things very very hard. I have found I can surprise some people with his damage output with the Choice Band set and has served as an efficient wall breaker as well as setting up the grassy terrain. I don't often Tera on Rillaboom since I find it to be more useful on other mons in most instances.

Sneasler @ Grassy Seed
Ability: Unburden
Tera Type: Flying
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Swords Dance
- Dire Claw
- Close Combat
- Acrobatics

Sneasler is the second core member of the team. I run a Grassy Seed set with Unburden to synergize with the grassy terrain that Rillaboom provides. This allows Sneasler to outspeed most of the OU tier. I've experimented with Acrobatics + Flying Tera and Night Slash with Dark Tera and I think I was finding more success with Night Slash as it allowed me to damage some mons like Gholdengo. I like to bring Sneasler in as a late game closer after I've taken care of some of the mons that can resist him a bit.

Gholdengo @ Grassy Seed
Ability: Good as Gold
Tera Type: Steel
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Nasty Plot
- Shadow Ball
- Make It Rain
- Recover

After I settled on the core I decided I needed to bring in some SPA fire power. I decided on Gholdengo due to his strength in the current meta. I decided on giving him grassy seed as well to further synergize with the grassy terrain. I appreciate Gholdengo's ability to prevent hazard clear and ability to wallbreak. I can also set up with Nasty Plots if people fall asleep on it or ignore his defensiveness with grassy seed defensive boost + grassy terrain reduced Earthquake damage.

Great Tusk @ Booster Energy
Ability: Protosynthesis
Tera Type: Steel
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Headlong Rush
- Close Combat
- Stealth Rock
- Rapid Spin

I decided I needed some form of Stealth Rock setter and Great Tusk seemed like the easy choice to me. I run an offensive set on him that can threaten bulkier mons from thinking they will get a free switch in while I try to set up rocks or clear hazards. I've been considering other sets such as running a Bulk-Up set as I feel that seems to block me quite easily. I've also considered taking Ice Spinner to hit other flying types.

Azumarill @ Sitrus Berry
Ability: Huge Power
Tera Type: Water
EVs: 252 HP / 252 Atk / 4 Def
Adamant Nature
- Aqua Jet
- Play Rough
- Belly Drum
- Superpower

Azumarill is a mon I added to try to deal with the glaring weakness I found to ground in the team, as well as bringing a lot of damage to the table. The priority move from Aqua Jet has also been useful for dealing with some annoying situations. I haven't gotten too much use out of this mon and think this is one of the main ones I would consider replacing for another option. It is nice to have a Fairy type to swap into dragons however.

Dragapult @ Choice Specs
Ability: Infiltrator
Tera Type: Fire
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Draco Meteor
- Shadow Ball
- Flamethrower
- U-turn

Dragapult has been a very useful part of the team due to his speed. I highly value Dragapults ability to naturally outspeed almost everything in OU and threaten it with hard hitting abilities. Infilitrator has also been useful in dealing with sub-set Iron Moths that try to set up on Rillaboom. I think this mon has been the most useful for me outside Rilla+Sneasler. I think running double ghost mons can lead to some difficult matchups and I'm unsure if it would be better to hold onto Dragapul or Gholdengo.

 

[Srn]

For your first time building, I think you've done a pretty good job! There's a few small tweaks I'd suggest and two pokemon changes.

For one big change, I'd use Rotom-Wash over Azumarill. Right now, it's a little difficult for your team to swap into opposing great tusk, which are often ice spinner+Headlong Rush/Earthquake. This is annoying because ice spinner can remove your grassy terrain, so it's important to have a solid switch in here. Rotom-W nicely tanks ice spinner and is immune to ground moves, so I think it's a good fit. Your team is imo a little weak to Kingambit as well, when it tera's to get past great tusk, it can be difficult to contain from there, so rotom-wash's Will-o-Wisp will be very helpful for that too.

Rotom-Wash @ Leftovers
Ability: Levitate
Tera Type: Steel
EVs: 248 HP / 216 Def / 44 Spe
Bold Nature
IVs: 0 Atk
- Hydro Pump
- Volt Switch
- Will-O-Wisp
- Protect / Eerie Impulse

The given speed evs will hit 219, which is faster than jolly Iron Hands, Azumarill, and Kingambit, all important targets to burn with WoW before you take a hit. Eerie Impulse drops special attack by two stages, which is very helpful vs opposing Ursaluna-Bloodmoon in conjunction with tera steel, but you can just stick with protect or thunder wave once that bear is banned (very likely)

The team lacks a ghost resist, on top of two ghost weaks this is not very good. That's why the next big change I suggest is Kingambit > Gholdengo. This does make your team a fair bit weaker to fighting types, so I think the best kind of Kingambit set here would be the most broken one, a simple SD Tera Blast Fairy Kingambit

Kingambit @ Leftovers
Ability: Supreme Overlord
Tera Type: Fairy
EVs: 248 HP / 252 Atk / 8 SpD
Adamant Nature
- Swords Dance
- Kowtow Cleave
- Sucker Punch
- Tera Blast

With leftovers+grassy terrain healing, this thing is a tanky beast and will end games easily. Just save it for last, keep your tera, and you will win games you shouldn't. Feel free to run more speed if you'd like.

On Great tusk, as you suspect, I would run Ice Spinner > Close Combat. Gliscor is a bastard and you don't want to give that mon any free switch-ins. I personally think Heavy-Duty Boots suits an offensive utility tusk more than booster energy, but the choice is up to you.

On Sneasler, I personally prefer this set over you current one:

Sneasler @ Grassy Seed
Ability: Unburden
Tera Type: Ghost
EVs: 252 Atk / 32 Def / 224 Spe
Adamant Nature
- Swords Dance
- Gunk Shot / Dire Claw
- Close Combat
- Shadow Claw

The given speed hits 332 to outspeed Thundurus-T and Manaphy if Unburden is used up. The reason I prefer Tera Ghost+Shadow claw is that Great tusk are very often ice spinner anyway for gliscor, while gliscor itself can still toxic you even if you tera fly. Meanwhile, Tera ghost+shadow claw is very helpful for getting past gholdengo, which is a huge roadblock otherwise, and tera ghost can protect you from Extremespeed. I prefer Gunk Shot for avoiding adverse contact effects, particularly static and flame body from Zapdos and Moltres. OHKO'ing them cleanly at +2 without suffering from their abilities is great imo, but Dire Claw's bullshit powers are worthwhile too.

Finally, don't forget Rillaboom's best move! Run Grassy Glide > Drain Punch, with Tera Grass > Fairy. A Tera Grass banded Grassy Glide under terrain can achieve incredible feats like revenge killing Iron Valiant, and greatly contributes to the overall speed control of your team in conjunction with Kingambit and Specs Dragapult.

That was a lot of changes, so here's a pokepaste of your team with all my suggested edits: https://pokepast.es/663b0503a4b7812e
Hope it plays well, have fun!

 

[Cadoo29]

Hello, thank you for taking the time to respond and offer suggestions. I really appreciate it. I'm excited to try these new changes. Thank you very much!