Cresselia (F) @ Choice Scarf  
Ability: Levitate  
Tera Type: Psychic  
EVs: 248 HP / 192 Def / 68 Spe  
Bold Nature  
IVs: 0 Atk  
- Psychic  
- Trick  
- Moonlight  
- Rest  

Diancie @ Weakness Policy  
Ability: Clear Body  
Tera Type: Rock  
EVs: 248 HP / 248 SpD / 12 Spe  
Careful Nature  
- Diamond Storm  
- Play Rough  
- Encore  
- Trick Room  

Rillaboom @ Grassy Seed  
Ability: Grassy Surge  
Tera Type: Grass  
EVs: 184 HP / 84 Atk / 240 Def  
Adamant Nature  
- Wood Hammer  
- Knock Off  
- Low Kick  
- Swords Dance  

Cresselia outspeeds Garchomp, rest in Physdef.  Diancie has max Spdef to help with Waters with a little speed creep for some Iron Hands sets, Play Rough for CM Raging Bolt.  Rillaboom tanks Meowscarada Triple Axel, rest in Attack