Demonlord Belzenlok

Flying, trample
When Demonlord Belzenlok enters the battlefield, exile cards from the top of your library until you exile a nonland card, then put that card into your hand. If the card's mana value is 4 or greater, repeat this process. Demonlord Belzenlok deals 1 damage to you for each card put into your hand this way.

Black Dragon

Flying
Acid Breath — When Black Dragon enters the battlefield, target creature an opponent controls gets -3/-3 until end of turn.

White Dragon

Flying
Cold Breath — When White Dragon enters the battlefield, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Red Dragon

Flying
Fire Breath — When Red Dragon enters the battlefield, it deals 4 damage to each opponent.

Kaalia of the Vast

Flying
Whenever Kaalia of the Vast attacks an opponent, you may put an Angel, Demon, or Dragon creature card from your hand onto the battlefield tapped and attacking that opponent.