Ambitious Dragonborn

Ambitious Dragonborn enters with X +1/+1 counters on it, where X is the greatest power among creatures you control and creature cards in your graveyard.

Miming Slime

Create an X/X green Ooze creature token, where X is the greatest power among creatures you control.

Avenging Hunter

Trample
When Avenging Hunter enters, you take the initiative.

Breath Weapon

Breath Weapon deals 2 damage to each non-Dragon creature.

Thriving Skyclaw

Flying
When Thriving Skyclaw enters, you get {E}{E}{E} (three energy counters).
Whenever Thriving Skyclaw attacks, you may pay {E}{E}{E}. If you do, put a +1/+1 counter on it.