Ravager of the Fells

Trample
Whenever this creature transforms into Ravager of the Fells, it deals 2 damage to target opponent or planeswalker and 2 damage to up to one target creature that player or that planeswalker's controller controls.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Ravager of the Fells.

Huntmaster of the Fells

Whenever this creature enters or transforms into Huntmaster of the Fells, create a 2/2 green Wolf creature token and you gain 2 life.
At the beginning of each upkeep, if no spells were cast last turn, transform Huntmaster of the Fells.

Huntmaster of the Fells // Ravager of the Fells

Increasing Savagery

Put five +1/+1 counters on target creature. If this spell was cast from a graveyard, put ten +1/+1 counters on that creature instead.
Flashback {5}{G}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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.

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.)

Mountain

Gravetiller Wurm

Trample
Morbid — Gravetiller Wurm enters with four +1/+1 counters on it if a creature died this turn.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

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.

Ghoultree

This spell costs {1} less to cast for each creature card in your graveyard.

Vorapede

Vigilance, trample
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.)

Silverpelt Werewolf

Whenever Silverpelt Werewolf deals combat damage to a player, draw a card.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Silverpelt Werewolf.

Lambholt Elder

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

Lambholt Elder // Silverpelt Werewolf

Moonscarred Werewolf

Vigilance
{T}: Add {G}{G}.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Moonscarred Werewolf.

Scorned Villager

{T}: Add {G}.
At the beginning of each upkeep, if no spells were cast last turn, transform Scorned Villager.

Scorned Villager // Moonscarred Werewolf

Forest

Kessig Recluse

Reach (This creature can block creatures with flying.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Dawntreader Elk

{G}, Sacrifice Dawntreader Elk: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Lost in the Woods

Whenever a creature attacks you or a planeswalker you control, reveal the top card of your library. If it's a Forest card, remove that creature from combat. Then put the revealed card on the bottom of your library.

Withengar Unbound

Flying, intimidate, trample (A creature with intimidate can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Whenever a player loses the game, put thirteen +1/+1 counters on Withengar Unbound.

Elbrus, the Binding Blade

Equipped creature gets +1/+0.
When equipped creature deals combat damage to a player, unattach Elbrus, the Binding Blade, then transform it.
Equip {1}

Elbrus, the Binding Blade // Withengar Unbound

Briarpack Alpha

Flash (You may cast this spell any time you could cast an instant.)
When Briarpack Alpha enters, target creature gets +2/+2 until end of turn.

Predator Ooze

Indestructible (Damage and effects that say "destroy" don't destroy this creature.)
Whenever this creature attacks, put a +1/+1 counter on it.
Whenever a creature dealt damage by this creature this turn dies, put a +1/+1 counter on this creature.

Krallenhorde Killer

{3}{G}: Krallenhorde Killer gets +4/+4 until end of turn. Activate only once each turn.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Krallenhorde Killer.

Wolfbitten Captive

{1}{G}: Wolfbitten Captive gets +2/+2 until end of turn. Activate only once each turn.
At the beginning of each upkeep, if no spells were cast last turn, transform Wolfbitten Captive.