Whoo boy i've been waiting for a thread like this one. I spend at least an hour daily using off-meta, weird sets because I tend to get bored of meta stuff, so now I finally get to share some of the better ones with you all! Fair warning, I tend to ramble so this is gonna be a pretty long one. Feel free to skim the sets if you like.
Are you tired of the same old physical walls? Landorus just not filling that flower-shaped hole in your heart? Well boy do I have the answer for you!
credit to AngeKrystaleen on DeviantArt for the art
I started using Vileplume about a month or two ago when RS Urshi was being a pain in the behind, and I searched for something(other than pex cuz that's boring ;) that resisted both of its stabs and wasn't weak to U-Turn. That's when I found this bad boy way down in the RU tier. Before I explain how it works, let's see the set.
Vileplume@Black Sludge
Ability: Effect Spore
252 HP / 252 Def / 4 SpD
Bold Nature
-Infestation/Corrosive Gas
-Strength Sap
-Giga Drain/Pollen Puff
-Sludge Bomb
The name of the game is walling. And how it gets done is one move. Strength Sap. SS is ridiculously powerful when combating physical attackers due to its ability to often heal plume for a majority if not all its health and reduce the damage of the subsequent hit save a crit. And as a physical wall it manages most of the tier besides those that hit it supereffectively. Some calcs below:
+2 252 Atk Garchomp Earthquake vs. 252 HP / 252+ Def Vileplume: 262-309 (74 - 87.2%) -- guaranteed 2HKO after Black Sludge recovery
252 Atk Landorus-Therian Earthquake vs. 252 HP / 252+ Def Vileplume: 142-168 (40.1 - 47.4%) -- guaranteed 3HKO after Black Sludge recovery
252+ Atk Choice Band Barraskewda Liquidation vs. 252 HP / 252+ Def Vileplume: 88-104 (24.8 - 29.3%) -- possible 5HKO after Black Sludge recovery
252+ Atk Iron Fist Melmetal Double Iron Bash (2 hits) vs. 252 HP / 252+ Def Vileplume: 222-264 (62.7 - 74.5%) -- approx. 2HKO after Black Sludge recovery
While not being the strongest physical wall, it can tank some hits, and strength sap the damage off. But with its strong Sp.Atk stat, even uninvested its able to threaten switch-ins with its STAB Sludge Bomb. But the real offensive potential lies in Infestation. Infestation lets Vileplume not only sponge hits, but trap those that it sponges hits from, inflict chip damage on the switch, or even trap and remove some of its switch-ins, namely ferrothorn. With Giga Drain and the chip from Infestation, you do approximately 10% per turn, assuming a min roll on Giga Drain and that they still have their leftovers, allowing you to massively chunk Ferro for a breaker later. And with Pollen Puff, you threaten to almost if not KO them, doing 76% total assuming min rolls every time and only 4 turns of trapping and leftovers being intact.
0 SpA Vileplume Pollen Puff vs. 252 HP / 252+ SpD Ferrothorn: 46-55 (13 - 15.6%) -- possibly the worst move ever(+12.5%per turn for Infestation, -6.25% for Leftovers)
0 SpA Vileplume Giga Drain vs. 252 HP / 252+ SpD Ferrothorn: 14-17 (3.9 - 4.8%) -- possibly the worst move ever
Onto the next one!
Froslass by Hakkasm on DeviantArt
Froslass is by far my favorite hazard setter I've ever used, and by-far the most effective one barring meta ones like Ferrothorn and Pex.
Froslass@Bright Powder
Ability: Cursed Body
252 Spe / 252 HP / 4 Def
Timid Nature
-Spikes
-Taunt
-Disable/Will-o-Wisp/Pain Split/Icy Wind
-Destiny Bond
This set will be familiar to fans of past-generation lower tiers, but I believe its of some use on Hyper-offensive squads in OU. The crux of the set is Spikes obv, but the utility comes in the other moves. Taunt is used for blocking opposing hazards, and is especially good since Froslass is faster than all relevant non-scarfed hazard setters besides Ribombee, who is outclassed by Galvantula anyway. Destiny Bond ensures that at the minimum Froslass can make a 1-1 trade, which can be taken advantage of in the teambuilder by using mons who capitalize on the removal of mons that Froslass lures in like Heatran and Volcarona. The final move is mostly left up to you, it can be Disable, which is nasty against opposing setters that might only run one offensive move, Will-o-Wisp to cripple physical attackers Froslass lures in like Excadrill, Pain Split to try and get more Cursed Body procks and set up more Spikes, or Icy Wind to offensively threaten Lando-T and not be helpful against opposing Taunts, or if your prediction is really on-point, slowing down the switch-in to Destiny Bond it the turn after. Destiny Bond in and of itself forces mindgames on the opponent that forces them play around it, which can often lead to extra layers of spikes on predicted switches. The item is mostly customizable, although my two favorites have been Rocky Helmet to punish U-Turns and BrightPowder to get clutch extra layers of spikes, although in theory you could do funky stuff like Ring Target Switcheroo if you crafted your team around it.
Art by Glitched Bat on DeviantArt
Dracozolt@Blunder Policy
Ability: Hustle
252 Atk/ 252 Spe / 4 HP
Adamant Nature
-Bolt Beak
-Dragon Rush
-Earthquake
-Iron Tail
Here's a fun one based off of FangFoe's post about Hustle and Blunder Policy. Dracozolt with Hustle and +2 Speed is terrifying. That's about it lmao. Dragon Rush has 60% accuracy under hustle so it's not unrealistic for it to miss, and if it hits, oh well, Dracozolt hits like a Freight Train anyway. Some notable calcs(although I doubt u need it, its Dracozolt):
252+ Atk Hustle Dracozolt Bolt Beak (170 BP) vs. 252 HP / 252+ Def Blissey: 690-813 (96.6 - 113.8%) -- 81.3% chance to OHKO
252+ Atk Hustle Dracozolt Bolt Beak (170 BP) vs. 252 HP / 0 Def Heatran: 363-427 (94 - 110.6%) -- 62.5% chance to OHKO
252+ Atk Hustle Dracozolt Bolt Beak (170 BP) vs. 248 HP / 220 Def Zapdos: 345-406 (90 - 106%) -- 37.5% chance to OHKO
And finally, the last one, for now...
Art by TsaoShin on DeviantArt
Sirfetchd@Choice Band
Ability: Scrappy
248 HP / 252 Atk / 8 SpD
Adamant Nature
-Close Combat
-First Impression
-Brave Bird
-Knock Off
So uhh, Sirfetch'd with a choice band is terrifying. This thing hits like a freight train going 180, pure and simple. Scrappy means nothing is immune to its Close Combats and prevents Lando from reducing your power with Intimidate, and even in OU there are very few things that resist the move(and most of them are 2HKO'd anyway). First Impression lets it have some use even late game when its at low health and everything on the opponent's board is faster than it. Knock Off annihilates Glowking that come in expecting CC and has utility removing items from mons Sirfetch'd can't handle like Lando and Fini. Some calcs:
252+ Atk Choice Band Sirfetch’d Brave Bird vs. 252 HP / 164+ Def Landorus-Therian: 185-218 (48.4 - 57%) -- guaranteed 2HKO after Stealth Rock and Leftovers recovery
252+ Atk Choice Band Sirfetch’d Brave Bird vs. 252 HP / 200 Def Clefable: 225-265 (57.1 - 67.2%) -- guaranteed 2HKO after Leftovers recovery
252+ Atk Choice Band Sirfetch’d Close Combat vs. 252 HP / 252+ Def Hippowdon: 213-252 (50.7 - 60%) -- guaranteed 2HKO after Stealth Rock and Leftovers recovery
252+ Atk Choice Band Sirfetch’d Close Combat vs. 248 HP / 8 Def Scizor: 330-388 (96.2 - 113.1%) -- 75% chance to OHKO
252+ Atk Choice Band Sirfetch’d Knock Off (97.5 BP) vs. 252 HP / 0 Def Slowking-Galar: 430-508 (109.1 - 128.9%) -- guaranteed OHKO
252+ Atk Choice Band Sirfetch’d Close Combat vs. 252 HP / 4 Def Tornadus-Therian: 198-234 (54.6 - 64.6%) -- guaranteed 2HKO
252+ Atk Choice Band Sirfetch’d Brave Bird vs. 252 HP / 4 Def Tornadus-Therian: 265-312 (73.2 - 86.1%) -- guaranteed 2HKO
252+ Atk Choice Band Sirfetch’d First Impression vs. 0 HP / 0 Def Weavile: 472-556 (167.9 - 197.8%) -- guaranteed OHKO
252+ Atk Choice Band Sirfetch’d First Impression vs. 0 HP / 0 Def Regieleki: 288-339 (95.6 - 112.6%) -- 75% chance to OHKO
And trust me, anything weak to its moves gets Thanos-snapped out of existence faster than you can say Dux. And the bulk investment means its bulky enough to take at least one hit from just about anything while at full health, making it a fantastic mon for VoltTurn and Spikes HO teams.
252 SpA Heatran Magma Storm vs. 248 HP / 8 SpD Sirfetch’d: 192-226 (58.7 - 69.1%) -- guaranteed 2HKO after trapping damage
252 SpA Tapu Koko Dazzling Gleam vs. 248 HP / 8 SpD Sirfetch’d: 248-294 (75.8 - 89.9%) -- guaranteed 2HKO
252 SpA Choice Specs Dragapult Shadow Ball vs. 248 HP / 8 SpD Sirfetch’d: 192-226 (58.7 - 69.1%) -- guaranteed 2HKO(and DM only KO's fromfull about 68% of the time).
0 Atk Garchomp Earthquake vs. 248 HP / 0 Def Sirfetch’d: 142-168 (43.4 - 51.3%) -- 6.3% chance to 2HKO
252 SpA Blacephalon Flamethrower vs. 248 HP / 0 SpD Sirfetch’d: 195-229 (59.6 - 70%) -- guaranteed 2HKO
chesto rest belch 
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