Mild-Mannered Librarian

{3}{G}: This creature becomes a Werewolf. Put two +1/+1 counters on it and you draw a card. Activate only once.

Prey Upon

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

Forest

Hunger of the Howlpack

Put a +1/+1 counter on target creature.
Morbid — Put three +1/+1 counters on that creature instead if a creature died this turn.

Spectral Hunt-Caller

{5}{G}: Creatures you control get +1/+1 and gain trample until end of turn.

Thriving Grove

This land enters tapped. As it enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

Predator's Howl

Create a 2/2 green Wolf creature token.
Morbid — Create three 2/2 green Wolf creature tokens instead if a creature died this turn.

Arlinn, Voice of the Pack

Each creature you control that's a Wolf or a Werewolf enters with an additional +1/+1 counter on it.
−2: Create a 2/2 green Wolf creature token.

Sporeback Wolf

During your turn, this creature gets +0/+2.

Bounding Wolf

Wolves

Feed the Pack

At the beginning of your end step, you may sacrifice a nontoken creature. If you do, create X 2/2 green Wolf creature tokens, where X is the sacrificed creature's toughness.

Kessig Cagebreakers

Whenever this creature attacks, create a 2/2 green Wolf creature token that's tapped and attacking for each creature card in your graveyard.

Ferocious Pup

When this creature enters, create a 2/2 green Wolf creature token.

Wolfwillow Haven

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G}.
{4}{G}, Sacrifice this Aura: Create a 2/2 green Wolf creature token. Activate only during your turn.