Arctozolt
Arctozolt is a good choice, but I think your set needs a tiny bit of work. You should replace Rock Slide with Stone Edge, as the extra power is worth the accuracy tradeoff. It lets you hit things like Darmanitan and other Ice types that your team can struggle with for extra power, which is always nice. Stomping Tantrum is solid, especially when paired with Stone Edge, but you could also opt for Low Kick. It enables you to hit Pokemon like Urshifu-Single Strike, Bisharp, and Tyranitar for big damage, and all three are top threats you have to watch out for. Try Heavy-Duty Boots or a Life Orb instead of Choice Scarf. Arctozolt is prone to getting worn down, or it would appreciate the boost from Life Orb. Here’s a possible revised set:
Arctozolt @ Heavy-Duty Boots / Life Orb
Ability: Slush Rush
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Bolt Beak
- Icicle Crash
- Stomping Tantrum / Low Kick
- Stone Edge
Ninetales-Alola
Icy Rock? No. Light Clay is a much better item, giving your team sorely needed defense in Aurora Veil, which is more useful than eight turns of hail most of the time. Get rid of Ice Beam and put on Blizzard for perfect accuracy STAB, or Freeze-Dry for weaker STAB that takes out threats like Pelipper, Barraskewda, and Dracovish. Ninetales-A is faster than the other weather setters, so it pays to have a way to take care of them. Consider Encore or Heal Bell over Dark Pulse, as both are helpful utility moves, and Dark Pulse doesn’t really hit too many things of note.
Ninetales-Alola @ Light Clay
Ability: Snow Warning
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Aurora Veil
- Moonblast
- Blizzard / Ice Beam
- Heal Bell / Encore
Darmanitan-Galar
You might want U-turn over Zen Headbutt, as that doesn’t hit a whole lot, and Darmanitan could use the pivoting option. Superpower is an alternative to Earthquake, so you can hit Pokemon like Tyranitar and Snorlax for big damage, but that’s ultimately up to you, as Earthquake nails quite a bit in itself. Choice Scarf should be used over Choice Band, as the boosts from Band + Scarf are better than Band + Band a lot of the time.
Darmanitan-Galar @ Choice Scarf
Ability: Gorilla Tactics
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Icicle Crash
- Earthquake / Superpower
- Fire Punch
- U-turn
Mamoswine
You want Choice Band over Leftovers. I use a Mamoswine on my Monotype team, and I can say from experience Band makes it a wonderful wallbreaker. It gives you another way to deal with threats like Weavile, Tyranitar, and Hippowdon, and allows you to punch holes in premier walls like Toxapex. Use Adamant instead of Jolly for more power, because Mamoswine won’t be outspeeding much anyways. Rock Slide should be swapped for Superpower or Stone Edge, and it should be self-explanatory as to why.
Mamoswine @ Choice Band
Ability: Thick Fat
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Earthquake
- Icicle Crash
- Ice Shard
- Stone Edge / Superpower
Weavile
While Pressure certainly isn’t the best Ability, it’s better than Pickpocket, as that can give you a detrimental item like Choice Specs. Use a Life Orb or Choice Band for more power. The set looks fine, but you could consider Low Kick over Icicle Crash for (you guessed it) heavy threats like Tyranitar and Urshifu.
Weavile @ Life Orb / Choice Band
Ability: Pressure
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Icicle Crash / Low Kick
- Fake Out
- Knock Off
- Ice Shard
Frosmoth
There is absolutely no reason you should be using Life Orb over Heavy-Duty Boots. Frosmoth is practically dead if Stealth Rock is up, which it often is, because people love hazards. I don’t understand why you don’t have Quiver Dance on this thing. Use Giga Drain or Hurricane over Air Slash, and swap Dazzling Gleam for Quiver Dance.
Frosmoth @ Life Orb
Ability: Ice Scales
EVs: 248 HP / 252 SpA / 8 SpD
Modest Nature
IVs: 0 Atk
- Blizzard
- Bug Buzz
- Quiver Dance
- Hurricane / Giga Drain
To be honest, Frosmoth isn’t very good in Monotype. For a special wallbreaker, how about Kyurem? With Specs, it can be absolutely devastating, and it hits a lot of Pokemon with a colourful movepool.
Kyurem @ Choice Specs
Ability: Pressure
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Freeze-Dry
- Draco Meteor
- Ice Beam
- Earth Power
I play Ice Monotype, so I tried to give advice based on my personal experiences. You could also use Glastrier or Avalugg over, say, Darmanitan-Galar, for more defensive presence. They don't have as much coverage, but it’s still a definite option. Glastrier can snowball quickly with Chilling Neigh, and Avalugg provides valuable support with Sturdy, Recover, and Rapid Spin.
Glastrier @ Leftovers
Ability: Chilling Neigh
EVs: 252 HP / 252 Atk / 4 SpD
Adamant Nature
- Substitute
- Swords Dance
- Icicle Crash
- High Horsepower
Avalugg @ Heavy-Duty Boots
Ability: Sturdy
EVs: 252 HP / 4 Atk / 252 Def
Impish Nature
- Rapid Spin
- Avalanche
- Body Press
- Recover
You can also consider Eviolite Piloswine over Mamoswine for more defense.
Honestly, you don't need both Mamoswine and Weavile for attacking. It does leave you vulnerable to Volcarona and other fire-types, Eviolite Piloswine is much better to handle those.
-Swastik
Piloswine @ Eviolite
Ability: Thick Fat
EVs: 252 HP / 4 Def / 252 SpD
Careful Nature
- Stealth Rock
- Earthquake
- Rock Slide
- Ice Shard
Hope I helped!
