Hydra Switches are probably Fairies or Steel Types so we can go Toxicroak to punish it, we have Rotom as moonblast pivot + Specs Draga with Tbolt for Corv and Pex+ Fight Immunity, Croak can punish Bisharp for Draga too

Toxicroak @ Life Orb  
Ability: Dry Skin  
EVs: 252 Atk / 4 SpD / 252 Spe  
Jolly Nature  
- Swords Dance  
- Sucker Punch  
- Drain Punch  
- Gunk Shot

Hydreigon @ Choice Scarf  
Ability: Levitate  
EVs: 252 SpA / 4 SpD / 252 Spe  
Timid Nature  
- Dark Pulse  
- Fire Blast  
- U-turn  
- Draco Meteor

Seismitoad @ Leftovers  
Ability: Water Absorb  
EVs: 248 HP / 252 Def / 8 SpD  
Impish Nature  
- Stealth Rock  
- Toxic  
- Earthquake  
- Scald

Rotom-Heat @ Heavy-Duty Boots  
Ability: Levitate  
Shiny: Yes  
EVs: 252 HP / 128 SpA / 128 Spe  
Modest Nature  
IVs: 0 Atk  
- Nasty Plot  
- Overheat  
- Volt Switch  
- Thunderbolt

Corviknight @ Leftovers  
Ability: Pressure  
EVs: 248 HP / 180 SpD / 80 Spe  
Careful Nature  
- U-turn  
- Roost  
- Defog  
- Brave Bird

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