Ravenous Harpy

Flying
{1}, Sacrifice another creature: Put a +1/+1 counter on Ravenous Harpy.

Plains

Bolas's Citadel

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

Severed Strands

As an additional cost to cast this spell, sacrifice a creature.
You gain life equal to the sacrificed creature's toughness. Destroy target creature an opponent controls.

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.

Wanderer's Strike

Exile target creature, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Liliana, Dreadhorde General

Whenever a creature you control dies, draw a card.
+1: Create a 2/2 black Zombie creature token.
−4: Each player sacrifices two creatures of their choice.
−9: Each opponent chooses a permanent they control of each permanent type and sacrifices the rest.

Dawn of Hope

Whenever you gain life, you may pay {2}. If you do, draw a card.
{3}{W}: Create a 1/1 white Soldier creature token with lifelink.

Final Payment

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

Cruel Celebrant

Whenever Cruel Celebrant or another creature or planeswalker you control dies, each opponent loses 1 life and you gain 1 life.

Pitiless Pontiff

{1}, Sacrifice another creature: Pitiless Pontiff gains deathtouch and indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Open the Graves

Whenever a nontoken creature you control dies, create a 2/2 black Zombie creature token.

Isolated Chapel

Isolated Chapel enters tapped unless you control a Plains or a Swamp.
{T}: Add {W} or {B}.

Doomed Dissenter

When Doomed Dissenter dies, create a 2/2 black Zombie creature token.

Epicure of Blood

Whenever you gain life, each opponent loses 1 life.

Oathsworn Vampire

Oathsworn Vampire enters tapped.
You may cast Oathsworn Vampire from your graveyard if you gained life this turn.

Ajani's Pridemate

Whenever you gain life, put a +1/+1 counter on this creature.

Ajani's Welcome

Whenever a creature you control enters, you gain 1 life.

God-Eternal Oketra

Double strike
Whenever you cast a creature spell, create a 4/4 black Zombie Warrior creature token with vigilance.
When God-Eternal Oketra dies or is put into exile from the battlefield, you may put it into its owner's library third from the top.

Orzhov Guildgate

This land enters tapped.
{T}: Add {W} or {B}.

Bloodmist Infiltrator

Whenever Bloodmist Infiltrator attacks, you may sacrifice another creature. If you do, Bloodmist Infiltrator can't be blocked this turn.

Swamp

Ill-Gotten Inheritance

At the beginning of your upkeep, Ill-Gotten Inheritance deals 1 damage to each opponent and you gain 1 life.
{5}{B}, Sacrifice Ill-Gotten Inheritance: It deals 4 damage to target opponent and you gain 4 life.

Vindictive Vampire

Whenever another creature you control dies, Vindictive Vampire deals 1 damage to each opponent and you gain 1 life.

Ob Nixilis's Cruelty

Target creature gets -5/-5 until end of turn. If that creature would die this turn, exile it instead.

God-Eternal Bontu

Menace
When God-Eternal Bontu enters, sacrifice any number of other permanents, then draw that many cards.
When God-Eternal Bontu dies or is put into exile from the battlefield, you may put it into its owner's library third from the top.

Reassembling Skeleton

{1}{B}: Return this card from your graveyard to the battlefield tapped.

Thallid Omnivore

{1}, Sacrifice another creature: Thallid Omnivore gets +2/+2 until end of turn. If a Saproling was sacrificed this way, you gain 2 life.