Experiment One

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Remove two +1/+1 counters from Experiment One: Regenerate Experiment One. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Llanowar Elves

Groundswell

Target creature gets +2/+2 until end of turn.
Landfall — If you had a land enter the battlefield under your control this turn, that creature gets +4/+4 until end of turn instead.

Icehide Golem

({S} can be paid with one mana from a snow source.)

Steel Leaf Champion

Steel Leaf Champion can't be blocked by creatures with power 2 or less.

Scythe Tiger

Shroud (This creature can't be the target of spells or abilities.)
When Scythe Tiger enters, sacrifice it unless you sacrifice a land.

Snow-Covered Forest

Rhonas's Last Stand

Create a 5/4 green Snake creature token. Lands you control don't untap during your next untap step.

Blossoming Defense

Target creature you control gets +2/+2 and gains hexproof until end of turn.

Groundbreaker

Trample, haste
At the beginning of the end step, sacrifice Groundbreaker.

Rancor

Enchant creature
Enchanted creature gets +2/+0 and has trample.
When Rancor is put into a graveyard from the battlefield, return Rancor to its owner's hand.

Strangleroot Geist

Haste
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)