Ghibli (Garchomp) (M) @ Focus Sash
EVs: 6 HP / 252 Atk / 252 Spe
Ability: Rough Skin
Jolly Nature
- Outrage
- Earthquake
- Swords Dance
- Iron Head / Fire Fang
Same exact strat for every other gen, SD turn 1 and kill as much stuff with chomp as you can. You replace fire fang for iron head since there are no shedinjas in the tree and because it's better for killing Togekiss and other fairies than Fire Fang will be useful. You miss out on skarmory coverage but who actually cares when you can just set up a bunch of SDs and oneshot it with outrage anyways lol. 

Mettaton (Metagross) @ Metagrossite
EVs: 6 HP / 252 Atk / 252 Spe
Ability: Clear Body
Jolly / Adamant Nature
- Iron Head
- Zen Headbutt
- Bullet Punch
- Hammer Arm / Earthquake
Same Mega set as Gen 6, tough claws is OPOP. You can also run EQ over Hammer Arm to avoid the speed drop and lower accuracy, though you'll miss out on the tough claws boost. EQ is also useful for beating enemy Mega Metagrosses since the tree trainers unfortunately have megas now. Don't forget about Meta's priority bullet punch for revenge killing!

Lilac (Suicune) @ Leftovers
EVs: 252 HP / 252 Def / 6 Spe
Ability: Pressure
Bold Nature
- Scald
- Ice Beam
- Calm Mind
- Rest
Suicune is unchanged from Gen 6, you just sit there and calm mind and then sweep everything. Don't be afraid to hard PP stall or fish for burns to cripple really scary threats like mega gyarados, mega metagross, or basically any big fuckoff mega mon that threatens to sweep your whole team! Sometimes scald burns are your only wincon if a mega mon starts to boost up with SD or dragon dances, so be mindful of this and stop them early on by walling them with suicune before they snowball out of hand if Meta or Chomp can't deal with them.