I WOuld Reccomend Either Shaymin-S or Darkria.
Kyogre:
Thunder
Water Spout
Surf
Ice Beam
Groudon:
Fire Punch
Swords Dance
Earthquake
STone Edge
Rayquaza:
Dragon Dance
Earthquake
Outrage
Extremespeed/Fire Blast
Lugia:
Reflect
Aeroblast
Toxic/Substitute
Light Screen
Mewtwo:
Thunder
Aura Sphere
Ice Beam
SHadow Ball
SHaymin-S
Substitute
Leech Seed
Energy Ball
Earth Power
Darkrai
Dark Void
Focus Blast
Dream Eater
Dark Pulse