Tropius crest: Nullifies its Grass type weaknesses, increases its Attack stat by 50%.
Serperior crest: Grants it Dragon type, makes it resist Ice type and Flying type.
Emboar crest: Grants it Rock Head, raises its speed by one stage every time it uses a Fire type physical move. (If it uses Flame Charge, its speed will raise by two stages.)
Samurott crest: Swaps its Special Attack and Speed stats, slash move (Razor Shell, Sacred Sword, X-Scissor, Fury Cutter, Night Slash, Slash and Burn, Cut, Slash, Air Slash) boosted in power by 50%.
Miltank crest: Grants it Serene Grace, Milk Drink can be used on its ally and party Pokemon in battle.
Ninjask crest: Attack scales with Speed.
Shedinja crest: Grants it Disguise (Gen 7 version) and Magic Guard.
Phione crest: Its base stats scale with Manaphy when Manaphy is in the party. Replaces its ability with Storm Drain.
Pangoro crest: Its base Attack and base Speed increase based on the amount of Fighting type and Dark type Pokemon in the party. Each Fighting type increases 5 base Attack stats. (max: 25) Each Dark type increases 10 base Speed stats. (max: 50) This does not include Pangoro itself.