And here is my selection for the question.:

Primal Groudon

• Earth Power
• Precipice Blades
• Fire Punch
• Lava Plume

Zacian (Crowned Sword)

• Behemoth Blade
• Steel Beam
• Play Rough
• Moonblast

Shaymin (Sky Forme)

• Seed Flare
• Seed Bomb
• Air Slash
• Rest

Mega Gengar

• Shadow Claw
• Night Shade
• Poison Jab
• Sludge Wave

Weavile - Pressure ability - Shell Bell held item

• Snarl
• Foul Play
• Icicle Crash
• Blizzard

Heliolisk - Dry Skin ability - Magnet held item

• Thunder Punch
• Parabolic Charge
• Hyper Voice
• Mega Kick

I think I would change Helolisk to Zamazenta with the Rusted Shield.

Need some tank, I got to some final tournaments here with my trevenant with harvest, drain punch, solar Ray, drain seeds and gigaimpact