Some days, I look at myself in the mirror and wonder if I'm honest-to-god clinically insane.
This is one of those days.
Offensive Stallbreaker Garchomp
Garchomp @ Leftovers
Ability: Rough Skin
EVs: 252 Atk / 4 Def / 252 Spe
Naive / Jolly Nature
- Whirlpool
- Earthquake
- Fire Blast / Stone Edge / Swords Dance
- Toxic
Turns out, when you scroll down to the very bottom of Garchomp's movepool in Showdown, you see a sight not meant for human eyes. This is similar to Magma Storm Heatran in that it traps a lot of switch-ins, but this set is more geared to dispatching offensive and balanced threats over defensive threats due to its lack of Taunt. Whirlpool traps a lot of things expecting to check Garchomp, like Steel-types, then allows you to either switch in with impunity, wipe them out, or set up in their faces. Toxic is meant to get some trickle damage on things that can't immediately force you out, like Hippowdon or defensive Lando-T.
Your third move is dependent on what you want to hit. Fire Blast 2HKOes Ferrothorn and M-Scizor, while Stone Edge lets you take care of Flying-types in general, namely Zapdos, Togekiss and SpDef Talonflame. Swords Dance is an interesting option to rack up 2HKOs on things that would otherwise wall you, like a 2HKO on Slowbro after SR. It's especially cool to set up on something like M-Scizor after trapping it with Whirlpool, since between Rough Skin and Whirlpool, there will be a lot of chip damage being dealt.
Rocky Helmet can be used, but this set appreciates the extra recovery against stall, especially if you decide to run a surprise Swords Dance. Similarly, Yache / Lum / Roseli Berry can be used with the EV spread of [252 HP / 164 Def / 76 SpD / 16 Spe Impish] to bluff an offensive SD set, forcing in a defensive 'mon that certainly won't appreciate Whirlpool + Toxic out of nowhere. SD on a defensive set still allows you to at least 2HKO most defensive threats, such as max Def Slowbro after SR and M-Venusaur.
EDIT: Vinc608 , SubSalac is already in the Preliminary Pokedex subforum. Not sure if it's used rarely enough to merit mention here.