Evolution Witness

{1}{G}: Adapt 2. (If this creature has no +1/+1 counters on it, put two +1/+1 counters on it.)
Whenever one or more +1/+1 counters are put on Evolution Witness, return target permanent card from your graveyard to your hand.

Basking Broodscale

Devoid (This card has no color.)
{1}{G}: Adapt 1. (If this creature has no +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever one or more +1/+1 counters are put on Basking Broodscale, you may create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this creature: Add {C}."

Fairgrounds Trumpeter

At the beginning of each end step, if a +1/+1 counter was put on a permanent under your control this turn, put a +1/+1 counter on Fairgrounds Trumpeter.

Sabertooth Mauler

At the beginning of your end step, if a creature died this turn, put a +1/+1 counter on Sabertooth Mauler and untap it.

Rot Shambler

Whenever another creature you control dies, put a +1/+1 counter on Rot Shambler.

Cloudfin Raptor

Flying
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.)

Woodland Stream

Woodland Stream enters tapped.
{T}: Add {G} or {U}.

Crocanura

Reach (This creature can block creatures with flying.)
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.)

Crowned Ceratok

Trample
Each creature you control with a +1/+1 counter on it has trample.

Vigean Hydropon

Graft 5 (This creature enters with five +1/+1 counters on it. Whenever another creature enters, you may move a +1/+1 counter from this creature onto it.)
Vigean Hydropon can't attack or block.

Thrummingbird

Flying
Whenever Thrummingbird deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Island

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.

Battering Krasis

Trample
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.)

Forced Adaptation

Enchant creature
At the beginning of your upkeep, put a +1/+1 counter on enchanted creature.