Morkrut Behemoth

As an additional cost to cast this spell, sacrifice a creature or pay {1}{B}.
Menace (This creature can't be blocked except by two or more creatures.)

Waildrifter

Flying
If Waildrifter would be put into a graveyard from anywhere, exile it instead.

Galedrifter

Flying
Disturb {4}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Galedrifter // Waildrifter

Gavony Trapper

Thraben Exorcism

Exile target Spirit, creature with disturb, or enchantment.

Eaten Alive

As an additional cost to cast this spell, sacrifice a creature or pay {3}{B}.
Exile target creature or planeswalker.

Fleshtaker

Whenever you sacrifice another creature, you gain 1 life and scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{1}, Sacrifice another creature: Fleshtaker gets +2/+2 until end of turn.

Bat Whisperer

When Bat Whisperer enters, if an opponent lost life this turn, create a 1/1 black Bat creature token with flying.

Crawl from the Cellar

Return target creature card from your graveyard to your hand. Put a +1/+1 counter on up to one target Zombie you control.
Flashback {3}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Odric's Outrider

Whenever Odric's Outrider or another creature you control dies, put a +1/+1 counter on target creature you control.

Candlegrove Witch

Coven — At the beginning of combat on your turn, if you control three or more creatures with different powers, Candlegrove Witch gains flying until end of turn.

Leeching Lurker

Lifelink
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Curse of Leeches

Enchant player
As this permanent transforms into Curse of Leeches, attach it to a player.
At the beginning of enchanted player's upkeep, they lose 1 life and you gain 1 life.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Curse of Leeches // Leeching Lurker

Island

Revenge of the Drowned

Target creature's owner puts it on their choice of the top or bottom of their library. You create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)

Duelcraft Trainer

First strike
Coven — At the beginning of combat on your turn, if you control three or more creatures with different powers, target creature you control gains double strike until end of turn.

Otherworldly Gaze

Surveil 3. (Look at the top three cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Swamp

Olivia's Midnight Ambush

Target creature gets -2/-2 until end of turn. If it's night, that creature gets -13/-13 until end of turn instead.

Cathar Commando

Flash
{1}, Sacrifice Cathar Commando: Destroy target artifact or enchantment.

Corpse Cobble

As an additional cost to cast this spell, sacrifice any number of creatures.
Create an X/X blue and black Zombie creature token with menace, where X is the total power of the sacrificed creatures.
Flashback {3}{U}{B} (You may cast this card from your graveyard for its flashback cost and any additional costs. Then exile it.)

Strangling Grasp

Enchant creature or planeswalker an opponent controls
At the beginning of your upkeep, enchanted permanent's controller sacrifices a nonland permanent of their choice, then that player loses 1 life.

Vengeful Strangler

Vengeful Strangler can't block.
When Vengeful Strangler dies, return it to the battlefield transformed under your control attached to target creature or planeswalker an opponent controls.

Vengeful Strangler // Strangling Grasp

Adeline, Resplendent Cathar

Vigilance
Adeline, Resplendent Cathar's power is equal to the number of creatures you control.
Whenever you attack, for each opponent, create a 1/1 white Human creature token that's tapped and attacking that player or a planeswalker they control.

Sunset Revelry

If an opponent has more life than you, you gain 4 life.
If an opponent controls more creatures than you, create two 1/1 white Human creature tokens.
If an opponent has more cards in hand than you, draw a card.

No Way Out

Target opponent discards two cards. You create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)

Secrets of the Key

Investigate. If this spell was cast from a graveyard, investigate twice instead. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Flashback {3}{U}

Sungold Barrage

Destroy target creature with toughness 4 or greater.

Curse of Silence

Enchant player
As Curse of Silence enters, choose a card name.
Spells with the chosen name enchanted player casts cost {2} more to cast.
Whenever enchanted player casts a spell with the chosen name, you may sacrifice Curse of Silence. If you do, draw a card.

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Slaughter Specialist

When Slaughter Specialist enters, each opponent creates a 1/1 white Human creature token.
Whenever a creature an opponent controls dies, put a +1/+1 counter on Slaughter Specialist.

Insectile Aberration

Delver of Secrets

At the beginning of your upkeep, look at the top card of your library. You may reveal that card. If an instant or sorcery card is revealed this way, transform Delver of Secrets.

Delver of Secrets // Insectile Aberration

Falcon Abomination

Flying
When Falcon Abomination enters, create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)

Hobbling Zombie

Deathtouch
When Hobbling Zombie dies, create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)

Ritual Guardian

Coven — At the beginning of combat on your turn, if you control three or more creatures with different powers, Ritual Guardian gains lifelink until end of turn.

Larder Zombie

Defender
Tap three untapped creatures you control: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Chilling Chronicle

{1}, {T}: Tap target nonland permanent. Transform Chilling Chronicle.

Mysterious Tome

{2}, {T}: Draw a card. Transform Mysterious Tome.

Mysterious Tome // Chilling Chronicle

Flip the Switch

Counter target spell unless its controller pays {4}. Create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)

Shipwreck Sifters

When Shipwreck Sifters enters, draw a card, then discard a card.
Whenever you discard a Spirit card or a card with disturb, put a +1/+1 counter on Shipwreck Sifters.

Awoken Demon

Ecstatic Awakener

{2}{B}, Sacrifice another creature: Draw a card, then transform Ecstatic Awakener. Activate only once each turn.

Ecstatic Awakener // Awoken Demon

Plains

Gavony Silversmith

When Gavony Silversmith enters, put a +1/+1 counter on each of up to two target creatures.

Morning Apparition

Flying, vigilance
If Morning Apparition would be put into a graveyard from anywhere, exile it instead.

Mourning Patrol

Vigilance
Disturb {3}{W} (You may cast this card from your graveyard transformed for its disturb cost.)