Diggersby for OU?

Diggersby @ Silk Scarf
Ability: Huge Power
EVs: 4 HP / 252 Atk / 252 Spe
Adamant Nature
- Earthquake
- Return
- Fire Punch
- Ice Punch

Heatran @ Leftovers
Ability: Flash Fire
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Magma Storm
- Earth Power
- Taunt
- Toxic

Tangrowth @ Assault Vest
Ability: Regenerator
EVs: 248 HP / 8 Def / 252 SpD
Sassy Nature
- Giga Drain
- Earthquake
- Knock Off
- Hidden Power [Ice]

Diancie-Mega @ Diancite
Ability: Magic Bounce
EVs: 4 Atk / 252 SpA / 252 Spe
Hasty Nature
- Diamond Storm
- Moonblast
- Earth Power
- Stealth Rock

Landorus-Therian @ Choice Scarf
Ability: Intimidate
EVs: 244 Atk / 68 Def / 196 Spe
Jolly Nature
- Earthquake
- U-turn
- Stone Edge
- Defog

Scolipede @ Waterium Z
Ability: Speed Boost
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Poison Jab
- Protect
- Aqua Tail
- Swords Dance