Valley Mightcaller

Trample
Whenever another Frog, Rabbit, Raccoon, or Squirrel you control enters, put a +1/+1 counter on this creature.

Burrowguard Mentor

Trample
Burrowguard Mentor's power and toughness are each equal to the number of creatures you control.

Regal Bunnicorn

Regal Bunnicorn's power and toughness are each equal to the number of nonland permanents you control.

Finneas, Ace Archer

Vigilance, reach
Whenever Finneas attacks, put a +1/+1 counter on each other creature you control that's a token or a Rabbit. Then if creatures you control have total power 10 or greater, draw a card.

Treeguard Duo

When this creature enters, until end of turn, target creature you control gains vigilance and gets +X/+X, where X is the number of creatures you control.

Warren Warleader

Offspring {2} (You may pay an additional {2} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Whenever you attack, choose one —
• Create a 1/1 white Rabbit creature token that's tapped and attacking.
• Attacking creatures you control get +1/+1 until end of turn.

Valley Questcaller

Whenever one or more other Rabbits, Bats, Birds, and/or Mice you control enter, scry 1.
Other Rabbits, Bats, Birds, and Mice you control get +1/+1.