Tentacruel (M) @ Leftovers
Trait: Rain Dish
EVs: 252 HP / 212 Def / 44 Spd
Bold Nature (+Def, -Atk)
- Scald
- Protect
- Rapid Spin
- Toxic Spikes
Politoed (M) @ Leftovers
Trait: Drizzle
EVs: 248 HP / 220 Def / 40 Spd
Bold Nature (+Def, -Atk)
- Scald
- Toxic
- Perish Song
- Protect
Tangrowth (M) @ Leftovers
Trait: Regenerator
EVs: 252 HP / 28 Atk / 228 Def
Relaxed Nature (+Def, -Spd)
- Giga Drain / Power Whip [Rock gem terrakion beat this team a lot once it became popular because Giga can't KO without the SpDef drop, so this is an option]
- Earthquake
- Sleep Powder
- Hidden Power [Ice]
Jirachi @ Leftovers
Trait: Serene Grace
EVs: 252 HP / 4 SAtk / 252 Spd
Timid Nature (+Spd, -Atk)
- Substitute
- Thunder
- Water Pulse
- Calm Mind
Skarmory (F) @ Leftovers
Trait: Sturdy
EVs: 252 HP / 236 Def / 20 Spd
Impish Nature (+Def, -SAtk)
- Brave Bird
- Spikes
- Roost
- Whirlwind
Chansey (F) @ Eviolite
Trait: Natural Cure
EVs: 252 HP / 192 Def / 64 SDef
Bold Nature (+Def, -Atk)
- Seismic Toss
- Toxic
- Stealth Rock
- Softboiled
This was the best team I've built, however it was built in BW1 OU so I'm not sure how great it will be in BW2 with the rise of some bigger threats but it could probably still be pretty solid in the right hands. The EVs were done a long time ago but here's what I remember.
Tentacruel: I think this outspeeds standard Gliscor
Politoed: Gets to the 180 or so benchmark to outrun skarm and CB Tar
Skarm: Outrun wobbuffet, politoed, some cb tar
Tangrowth: The 28 atk is from a set known as "Heists defensive tangrowth", I have no idea what they do but I kept them on for some reason.
Chansey: Never 2HKO'd by +6 celebi
Jirachi is just standard to maximize speed and bulk, the idea is to lure in ferrothorn [a common nuisance to rain stall] and set up a sub on him!