Dialga

SteelDragon
Weak toFightingGround
ResistsNormalWaterElectricGrassPoisonFlyingPsychicBugRockDarkSteel

Top Counters

Alakazam (Mega)
Counter|Focus Blast
Groudon (Primal)
Mud Shot|Precipice Blades, Earthquake
Gengar (Mega)
Hex|Focus Blast, Drain Punch
Garchomp (Mega)
Mud Shot|Earthquake, Earth Power
Latios (Mega)
Dragon Breath|Aura Sphere

Budget Picks

Haxorus
Counter|Earthquake
Alakazam
Counter|Focus Blast
Dragonite
Dragon Breath|Superpower
Gengar
Hex|Focus Blast, Drain Punch
Excadrill
Mud Slap|Earthquake, Drill Run