Wreath of Geists

Enchant creature
Enchanted creature gets +X/+X, where X is the number of creature cards in your graveyard.

Boneyard Wurm

Boneyard Wurm's power and toughness are each equal to the number of creature cards in your graveyard.

Forest

Gutter Grime

Whenever a nontoken creature you control dies, put a slime counter on Gutter Grime, then create a green Ooze creature token with "This creature's power and toughness are each equal to the number of slime counters on Gutter Grime."

Prey Upon

Target creature you control fights target creature you don't control. (Each deals damage equal to its power to the other.)

Ambush Viper

Caravan Vigil

Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Morbid — You may put that card onto the battlefield instead of putting it into your hand if a creature died this turn.

Woodland Sleuth

Morbid — When Woodland Sleuth enters, if a creature died this turn, return a creature card at random from your graveyard to your hand.

Howlpack of Estwald

At the beginning of each upkeep, if a player cast two or more spells last turn, transform Howlpack of Estwald.

Villagers of Estwald

At the beginning of each upkeep, if no spells were cast last turn, transform Villagers of Estwald.

Villagers of Estwald // Howlpack of Estwald

Lumberknot

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
Whenever a creature dies, put a +1/+1 counter on Lumberknot.

Gatstaf Howler

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Gatstaf Howler.

Gatstaf Shepherd

At the beginning of each upkeep, if no spells were cast last turn, transform Gatstaf Shepherd.

Gatstaf Shepherd // Gatstaf Howler

Garruk, the Veil-Cursed

+1: Create a 1/1 black Wolf creature token with deathtouch.
−1: Sacrifice a creature. If you do, search your library for a creature card, reveal it, put it into your hand, then shuffle.
−3: Creatures you control gain trample and get +X/+X until end of turn, where X is the number of creature cards in your graveyard.

Garruk Relentless

When Garruk Relentless has two or fewer loyalty counters on him, transform him.
0: Garruk Relentless deals 3 damage to target creature. That creature deals damage equal to its power to him.
0: Create a 2/2 green Wolf creature token.