Death Denied

Return X target creature cards from your graveyard to your hand.

Thraben Inspector

When Thraben Inspector enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Unearth

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling {2} ({2}, Discard this card: Draw a card.)

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Innocent Blood

Plains

Doomed Traveler

When Doomed Traveler dies, create a 1/1 white Spirit creature token with flying.

Soul Warden

Whenever another creature enters, you gain 1 life.

Bloodthrone Vampire

Sacrifice a creature: Bloodthrone Vampire gets +2/+2 until end of turn.

Orzhov Basilica

Orzhov Basilica enters tapped.
When Orzhov Basilica enters, return a land you control to its owner's hand.
{T}: Add {W}{B}.

Unruly Mob

Whenever another creature you control dies, put a +1/+1 counter on Unruly Mob.

Graf Rats

At the beginning of combat on your turn, if you both own and control Graf Rats and a creature named Midnight Scavengers, exile them, then meld them into Chittering Host.

Carrion Feeder

Carrion Feeder can't block.
Sacrifice a creature: Put a +1/+1 counter on Carrion Feeder.

Hunted Witness

When Hunted Witness dies, create a 1/1 white Soldier creature token with lifelink.

Imperious Oligarch

Vigilance
Afterlife 1 (When this creature dies, create a 1/1 white and black Spirit creature token with flying.)

Vicious Offering

Kicker—Sacrifice a creature. (You may sacrifice a creature in addition to any other costs as you cast this spell.)
Target creature gets -2/-2 until end of turn. If this spell was kicked, that creature gets -5/-5 until end of turn instead.

Bone Splinters

As an additional cost to cast this spell, sacrifice a creature.
Destroy target creature.

Midnight Scavengers

When Midnight Scavengers enters, you may return target creature card with mana value 3 or less from your graveyard to your hand.
(Melds with Graf Rats.)

Final Payment

As an additional cost to cast this spell, pay 5 life or sacrifice a creature or enchantment.
Destroy target creature.

Swamp

Mortician Beetle

Whenever a player sacrifices a creature, you may put a +1/+1 counter on Mortician Beetle.

Scoured Barrens

Scoured Barrens enters tapped.
When Scoured Barrens enters, you gain 1 life.
{T}: Add {W} or {B}.

Vulturous Aven

Flying
Exploit (When this creature enters, you may sacrifice a creature.)
When Vulturous Aven exploits a creature, you draw two cards and you lose 2 life.