Koraidon @ Heat Rock  
Ability: Orichalcum Pulse  
Tera Type: Fire  
EVs: 252 Atk / 4 SpD / 252 Spe  
Jolly Nature  
- Flare Blitz  
- U-turn  
- Collision Course  
- Dragon Claw 
(Heat Rock is a niche item on Koraidon, I know.) 

Chi-Yu @ Choice Specs  
Ability: Beads of Ruin  
Tera Type: Fire  
EVs: 252 SpA / 4 SpD / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Overheat  
- Flamethrower  
- Dark Pulse  
- Psychic  

Flutter Mane @ Choice Specs  
Ability: Protosynthesis  
Tera Type: Fairy  
EVs: 252 SpA / 4 SpD / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Moonblast  
- Shadow Ball  
- Power Gem  
- Mystical Fire  

Groudon @ Heat Rock
Ability: Drought
Tera Type: Fire
EVs: 252 Atk / 4 Def / 252 Spe 
Adamant Nature
- Heat Crash
- Dragon Claw
- Precipice Blades
- Swords Dance

Kyurem-Black @ Loaded Dice  
Ability: Teravolt  
Tera Type: Fire  
EVs: 252 Atk / 4 SpD / 252 Spe  
Naughty Nature  
- Dragon Dance  
- Icicle Spear  
- Scale Shot  
- Tera Blast  

Smeargle @ Focus Sash  
Ability: Own Tempo  
Tera Type: Normal  
EVs: 252 HP / 4 Atk / 252 Spe  
Jolly Nature  
- Sticky Web  
- Rapid Spin  
- Gastro Acid  
- Fake Out