Blissey
...no. Blissey only has base 10 Attack and base 75 Special Attack. Healer also only works in Doubles so Natural Cure is the better ability. Soft-Boiled is mandatory on Blissey. You should either be using the standard set that counters Kyogre, or the Heavy-Duty Boots one.
Blissey @ Utility Umbrella
Ability: Natural Cure
EVs: 4 HP / 252 Def / 252 SpD
Calm Nature
- Soft-Boiled
- Teleport / Confide
- Seismic Toss / Toxic
- Aromatherapy / Seismic Toss
Ferrothorn
Iron Barbs is a much better ability because it can punish contact moves, and Ferrothorn loves wearing things down. Ferrothorn should be using Leftovers since Aguav Berry isn't a good item, and it should use a Specially Defensive spread instead to better handle non Block+Sheer Cold Kyogre. Having Ferrothorn on your team makes it a little passive, so why not Eternatus? I'm keeping Blissey because it can switch into both Kyogre and Eternatus.
Eternatus @ Black Sludge
Ability: Pressure
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
- Dynamax Cannon
- Flamethrower
- Recover
- Toxic
Garchomp
Why do you have 3 Dragon moves yet no STAB Earthquake, and why are you using Black Glasses. A better set would be Earthquake - Scale Shot - Stone Edge - Swords Dance / Stealth Rock with Life Orb as the item, but let's not act like Garchomp is even remotely viable in Anything Goes. Zygarde is better on this team, which looks like Balance or so far. Or, you could use Swords Dance Groudon, one of the best Dynamaxers in Anything Goes.
Zygarde @ Leftovers
Ability: Power Construct
EVs: 252 HP / 208 Def / 48 SpD
Impish Nature
- Thousand Arrows
- Rest
- Glare
- Coil
Zygarde @ Leftovers
Ability: Power Construct
EVs: 16 HP / 224 Atk / 36 Def / 232 Spe
Impish Nature
- Thousand Arrows
- Dragon Dance
- Substitute
- Dragon Tail
Groudon @ Life Orb
Ability: Drought
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Precipice Blades
- Stone Edge
- Aerial Ace
- Swords Dance
Melmetal
Why are you using Choice Specs on a Pokemon with Thunder Wave, 2 Physical moves, and only 1 Special move, which also is the same type as one of your physical moves? Choice Band, Leftovers, or Assault Vest are preferred with a different EV spread than yours and an Adamant nature on Choice Band and Leftovers sets and Careful on Assault Vest builds. However, Melmetal is not good in AG, as there is 0 reason to use it over Zacian-Crowned and Necrozma-Dusk Mane.
Zacian-Crowned @ Rusted Sword
Ability: Intrepid Sword
EVs: 252 Atk / 4 Def / 252 Spe (Jolly) or 252 HP / 252 Atk / 4 Def (Adamant)
Jolly/Adamant Nature
- Behemoth Blade
- Close Combat
- Wild Charge
- Swords Dance / Play Rough
Necrozma-Dusk Mane @ Leftovers / Rocky Helmet / Heavy-Duty Boots
Ability: Prism Armor
EVs: 252 HP / 252 Def / 4 SpD
Impish Nature
- Sunsteel Strike
- Stealth Rock / Knock Off
- Morning Sun / Moonlight
- Thunder Wave / Toxic
Necrozma-Dusk Mane @ Weakness Policy
Ability: Prism Armor
EVs: 80 HP / 252 Atk / 176 Spe
Adamant Nature
- Sunsteel Strike
- Dragon Dance
- Stone Edge
- Earthquake / Psychic Fangs
Regieleki
That set is...very suboptimal. Regieleki is the fastest Pokemon and outspeeds Choice Scarfers from Ubers's overcrowded Base 90 Speed tier, as well as some base 95s and base 100s. There is absolutely no reason for Agility to be here. On a Pokemon that does so much damage and is walled by Ground types, Thunder Wave is also pointless. Regieleki's main selling point in Anything Goes stems from its Dual Screens set, but this team can't use them effectively. You should probably just use an offensive Pokemon like Kyogre or Calyrex-Ghost instead. You can find Kyogre's Specs/Scarf set here, and Calyrex-Ghost's Specs set here. I'll be posting some Kyogre sets not mentioned on the Smogon page here.
Kyogre @ Leftovers
Ability: Drizzle
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
- Scald
- Block
- Rest
- Calm Mind
Kyogre @ Leftovers
Ability: Drizzle
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
- Scald
- Sheer Cold
- Rest
- Sleep Talk
Dragapult
Why are you putting Rocky Helmet on a Pokemon that struggles to take hits? That set also isn't good, just like Dragapult itself. If you chose Kyogre for the 5th slot, use Calyrex-Ghost in the 6th slot. Either that, or use a defensive Pokemon like Ho-oh (set can be found here) or Specially Defensive Yveltal (here for the SpD Yveltal set).
