Froslass-Mega @ Froslassite
Ability: Cursed Body
Level: 50
Shiny: Yes
EVs: 2 HP / 32 SpA / 32 Spe
Modest Nature
- Blizzard
- Shadow Ball
- Thunderbolt
- Nasty Plot
The obvious choice for a mega in a snow team. Snow warning on the mega lets it set up snow whenever it wants, blizzard in 100% accurate in snow, shadow ball is STAB, thunderbolt is coverage, and it can get a free nasty plot via substitute.
Ninetales-Alola (F) @ Focus Sash
Ability: Snow Warning
Level: 50
EVs: 2 HP / 32 SpA / 32 Spe
Timid Nature
- Freeze-Dry
- Aurora Veil
- Moonblast
- Encore
Ninetales is my secondary snow setter. Freeze-dry gives coverage for water types, aurora veil boosts the team's defences, moonblast is STAB, and encore can be pretty annoying if used right.
Orthworm (M) @ Mental Herb
Ability: Earth Eater
Level: 50
EVs: 2 HP / 32 Atk / 32 Def
Adamant Nature
- Iron Tail
- Body Press
- Coil
- Shed Tail
I have a love-hate relationship with Orthworm. On one hand, it's the cornerstone of the team with shed tail, and it can also hold it's own if it sets up with coil. But on the other hand, it does basically the same with as the Hisuian Goodra I wanted to use (H-Goodra is my favourite mon), but better.
Delphox-Mega (F) @ Delphoxite
Ability: Blaze
Level: 50
Shiny: Yes
EVs: 2 HP / 32 SpA / 32 Spe
Modest Nature
- Heat Wave
- Psychic
- Dazzling Gleam
- Nasty Plot
Mega Delphox is my secondary mega if Froslass has bad matchups. Honestly, this was kind of an impulse decision; I saw levitate and just immediately added it. Heat wave and psychic are STAB, dazzling is coverage and nasty plot is for the same reasons as Froslass.
Garchomp (M) @ Choice Scarf
Ability: Rough Skin
Level: 50
EVs: 2 HP / 32 Atk / 32 Spe
- Dragon Claw
- Earthquake
- Rock Slide
- Protect
I needed a ground type to synergise with Orthworm, and Garchomp is the best one right now. Dragon claw and earthquake are STAB, rock slide is coverage, blah blah blah.
Rotom-Wash @ Sitrus Berry
Ability: Levitate
Level: 50
EVs: 32 HP / 2 Def / 32 SpD
Calm Nature
- Electroweb
- Hydro Pump
- Will-O-Wisp
- Protect
Rotom provides some nice disruption plus water STAB. Electroweb is basically electric type icy wind, hydro pump is STAB, and will-o-wisp shuts down physical attackers.
P.S. I totally didn't steal like half of this team from Wolfey