Eternatus @ Leftovers
Ability: Pressure
EVs: 248 HP / 88 Def / 164 SpD / 8 Spe or 80 HP / 252 SpD / 176 Spe
Tera Type: Fairy / Water
Timid Nature
IVs: 0 Atk 
- Recover
- Toxic Spikes / Toxic
- Sludge Bomb / Flamethrower / Toxic Spikes / Mystical Fire  
- Dynamax Cannon

Eternatus @ Power Herb
Ability: Pressure
EVs: 252 SpA / 4 SpD / 252 Spe
Tera Type: Dragon / Fire
Timid Nature
- Meteor Beam
- Dynamax Cannon
- Sludge Bomb
- Flamethrower / Fire Blast

Eternatus @ Power Herb  
Ability: Pressure  
Tera Type: Fairy  
EVs: 4 Def / 252 SpA / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Recover  
- Meteor Beam  
- Dynamax Cannon  
- Fire Blast

Eternatus @ Shucca Berry 
Ability: Pressure  
Tera Type: Fairy
EVs: 240 HP / 108 Def / 152 SpD / 8 Spe 
Timid Nature  
IVs: 0 Atk  
- Toxic 
- Toxic Spikes  
- Recover  
- Dynamax Cannon / Flamethrower