Rain OU

Politoed (F) @ Damp Rock
Ability: Drizzle
Shiny: Yes
EVs: 252 HP / 4 Def / 252 SpD
Calm Nature
- Encore
- Endeavor
- Protect
- Perish Song / Scald

If you dont want to run politoed, run pelipper:

Pelipper @ Damp Rock
Ability: Drizzle
EVs: 248 HP / 252 Def / 8 SpA
Bold Nature
- Hurricane
- Scald
- Roost
- U-turn

Dragonite (F) @ Weakness Policy
Ability: Multiscale
EVs: 4 HP / 252 SpA / 252 Spe
Modest Nature
IVs: 0 Atk
- Thunder
- Surf
- Hurricane
- Agility

Sliggoo (F) @ Eviolite
Ability: Hydration
Shiny: Yes
EVs: 252 HP / 4 SpA / 252 SpD
Calm Nature
IVs: 0 Atk
- Muddy Water
- Rest
- Toxic
- Rain Dance

Shelmet @ Eviolite
Ability: Hydration
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
IVs: 0 Atk
- Rest
- Acid Armor
- Toxic
- Spikes

Garchomp (M) @ Leftovers
Ability: Rough Skin
Shiny: Yes
EVs: 252 Def / 4 SpD / 252 Spe
Jolly Nature
- Dragon Claw
- Earthquake
- Swords Dance
- Substitute

Magearna @ Leftovers
Ability: Soul-Heart
EVs: 252 HP / 252 SpA / 4 SpD
Modest Nature
IVs: 0 Atk
- Fleur Cannon
- Flash Cannon
- Aura Sphere
- Shift Gear