Krallenhorde Howler

Creature spells you cast cost {1} less to cast.
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Krallenhorde Howler.

Duskwatch Recruiter

{2}{G}: Look at the top three cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in any order.
At the beginning of each upkeep, if no spells were cast last turn, transform Duskwatch Recruiter.

Duskwatch Recruiter // Krallenhorde Howler

Intrepid Provisioner

Trample
When Intrepid Provisioner enters, another target Human you control gets +2/+2 until end of turn.

Olivia's Bloodsworn

Flying
Olivia's Bloodsworn can't block.
{R}: Target Vampire gains haste until end of turn.

Mindwrack Demon

Flying, trample
When Mindwrack Demon enters, mill four cards.
Delirium — At the beginning of your upkeep, you lose 4 life unless there are four or more card types among cards in your graveyard.

Loam Dryad

{T}, Tap an untapped creature you control: Add one mana of any color.

One of the Pack

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

Solitary Hunter

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

Solitary Hunter // One of the Pack

Forest

Diregraf Colossus

Diregraf Colossus enters with a +1/+1 counter on it for each Zombie card in your graveyard.
Whenever you cast a Zombie spell, create a tapped 2/2 black Zombie creature token.

Twins of Maurer Estate

Madness {2}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Swamp

Gisa's Bidding

Create two 2/2 black Zombie creature tokens.
Madness {2}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Traverse the Ulvenwald

Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Delirium — If there are four or more card types among cards in your graveyard, instead search your library for a creature or land card, reveal it, put it into your hand, then shuffle.

Biting Rain

All creatures get -2/-2 until end of turn.
Madness {2}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Merciless Resolve

As an additional cost to cast this spell, sacrifice a creature or land.
Draw two cards.

Seasons Past

Return any number of cards with different mana values from your graveyard to your hand. Put Seasons Past on the bottom of its owner's library.

Timber Shredder

Trample
At the beginning of each upkeep, if a player cast two or more spells last turn, transform Timber Shredder.

Hinterland Logger

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

Hinterland Logger // Timber Shredder

Shamble Back

Exile target creature card from a graveyard. Create a 2/2 black Zombie creature token. You gain 2 life.

Stallion of Ashmouth

Delirium — {1}{B}: Stallion of Ashmouth gets +1/+1 until end of turn. Activate only if there are four or more card types among cards in your graveyard.

Alms of the Vein

Target opponent loses 3 life and you gain 3 life.
Madness {B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Vessel of Nascency

{1}{G}, Sacrifice Vessel of Nascency: Reveal the top four cards of your library. You may put an artifact, creature, enchantment, land, or planeswalker card from among them into your hand. Put the rest into your graveyard.

Rabid Bite

Target creature you control deals damage equal to its power to target creature you don't control.

Dead Weight

Enchant creature
Enchanted creature gets -2/-2.

Kessig Dire Swine

Delirium — Kessig Dire Swine has trample as long as there are four or more card types among cards in your graveyard.

Vessel of Malignity

{1}{B}, Sacrifice Vessel of Malignity: Target opponent exiles two cards from their hand. Activate only as a sorcery.