Yahenni, Undying Partisan

Haste
Whenever a creature an opponent controls dies, put a +1/+1 counter on Yahenni, Undying Partisan.
Sacrifice another creature: Yahenni gains indestructible until end of turn.

Grave Betrayal

Whenever a creature you don't control dies, return it to the battlefield under your control with an additional +1/+1 counter on it at the beginning of the next end step. That creature is a black Zombie in addition to its other colors and types.

Overseer of the Damned

Flying
When Overseer of the Damned enters the battlefield, you may destroy target creature.
Whenever a nontoken creature an opponent controls dies, create a tapped 2/2 black Zombie creature token.

Abnormal Endurance

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control."

Bastion of Remembrance

When Bastion of Remembrance enters the battlefield, create a 1/1 white Human Soldier creature token.
Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.

Plague Wind

Destroy all creatures you don't control. They can't be regenerated.

Carrion Feeder

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

Gravecrawler

Gravecrawler can't block.
You may cast Gravecrawler from your graveyard as long as you control a Zombie.

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Necrosynthesis

Enchant creature
Enchanted creature has "Whenever another creature dies, put a +1/+1 counter on this creature."
When enchanted creature dies, look at the top X cards of your library, where X is its power. Put one of those cards into your hand and the rest on the bottom of your library in a random order.

Falkenrath Noble

Flying
Whenever Falkenrath Noble or another creature dies, target player loses 1 life and you gain 1 life.

Braids, Arisen Nightmare

At the beginning of your end step, you may sacrifice an artifact, creature, enchantment, land, or planeswalker. If you do, each opponent may sacrifice a permanent that shares a card type with it. For each opponent who doesn't, that player loses 2 life and you draw a card.

Merciless Executioner

When Merciless Executioner enters the battlefield, each player sacrifices a creature.

Unspeakable Symbol

Pay 3 life: Put a +1/+1 counter on target creature.

Plaguecrafter

When Plaguecrafter enters the battlefield, each player sacrifices a creature or planeswalker. Each player who can't discards a card.

Necropolis

Defender (This creature can't attack.)
Exile a creature card from your graveyard: Put X +0/+1 counters on Necropolis, where X is the exiled card's mana value.

Novice Dissector

{1}, Sacrifice another creature: Put a +1/+1 counter on target creature. Activate only as a sorcery.

Kamber, the Plunderer

Partner with Laurine, the Diversion (When this creature enters the battlefield, target player may put Laurine into their hand from their library, then shuffle.)
Lifelink
Whenever a creature an opponent controls dies, you gain 1 life and create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")

Dread Return

Return target creature card from your graveyard to the battlefield.
Flashback—Sacrifice three creatures. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Retribution of the Ancients

{B}, Remove X +1/+1 counters from among creatures you control: Target creature gets -X/-X until end of turn.

Astarion's Thirst

Exile target creature. Put X +1/+1 counters on a commander creature you control, where X is the power of the creature exiled this way.

In Garruk's Wake

Destroy all creatures you don't control and all planeswalkers you don't control.

Chain Devil

Animate Chains — When Chain Devil enters the battlefield, each player sacrifices a nontoken creature.

Zulaport Cutthroat

Whenever Zulaport Cutthroat or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Black Market

Whenever a creature dies, put a charge counter on Black Market.
At the beginning of your precombat main phase, add {B} for each charge counter on Black Market.

Lim-Dûl the Necromancer

Whenever a creature an opponent controls dies, you may pay {1}{B}. If you do, return that card to the battlefield under your control. If it's a creature, it's a Zombie in addition to its other creature types.
{1}{B}: Regenerate target Zombie.

Skyclave Shadowcat

{1}{B}, Sacrifice another creature: Put a +1/+1 counter on Skyclave Shadowcat.
Whenever a creature you control with a +1/+1 counter on it dies, draw a card.

Smothering Abomination

Devoid (This card has no color.)
Flying
At the beginning of your upkeep, sacrifice a creature.
Whenever you sacrifice a creature, draw a card.

Eternal Thirst

Enchant creature
Enchanted creature has lifelink and "Whenever a creature an opponent controls dies, put a +1/+1 counter on this creature." (Damage dealt by a creature with lifelink also causes its controller to gain that much life.)

Feign Death

Until end of turn, target creature gains "When this creature dies, return it to the battlefield tapped under its owner's control with a +1/+1 counter on it."

Lokhust Heavy Destroyer

Flying
Enmitic Exterminator — When Lokhust Heavy Destroyer enters the battlefield, each player sacrifices a creature.
Unearth {5}{B}{B}{B} ({5}{B}{B}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Bind Spirit

Return target creature card from your graveyard to your hand. (Then exile this card. You may cast the artifact later from exile.)

Ghost Lantern

Whenever a creature you control dies, put a +1/+1 counter on equipped creature.
Equip {1}

Ghost Lantern // Bind Spirit

Pawn of Ulamog

Whenever Pawn of Ulamog or another nontoken creature you control dies, you may create a 0/1 colorless Eldrazi Spawn creature token. It has "Sacrifice this creature: Add {C}."

Feast on the Fallen

At the beginning of each upkeep, if an opponent lost life last turn, put a +1/+1 counter on target creature you control.

Cauldron's Gift

Adamant — If at least three black mana was spent to cast this spell, mill four cards.
You may choose a creature card in your graveyard. If you do, return it to the battlefield with an additional +1/+1 counter on it.

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Undying Malice

Demon's Disciple

When Demon's Disciple enters the battlefield, each player sacrifices a creature or planeswalker.

Gravelighter

Flying
When Gravelighter enters the battlefield, draw a card if a creature died this turn. Otherwise, each player sacrifices a creature.

Phyrexian Reclamation

{1}{B}, Pay 2 life: Return target creature card from your graveyard to your hand.

Demonic Gifts

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield under its owner's control."

Sifter of Skulls

Devoid (This card has no color.)
Whenever another nontoken creature you control dies, create a 1/1 colorless Eldrazi Scion creature token. It has "Sacrifice this creature: Add {C}." ({C} represents colorless mana.)

Sadistic Glee

Enchant creature
Whenever a creature dies, put a +1/+1 counter on enchanted creature.

Agent of the Shadow Thieves

Commander creatures you own have "Whenever this creature attacks a player, if no opponent has more life than that player, put a +1/+1 counter on this creature. It gains deathtouch and indestructible until end of turn."

Vogar, Necropolis Tyrant

Menace
Whenever another creature dies during your turn, put a +1/+1 counter on Vogar, Necropolis Tyrant.
When Vogar dies, draw a card for each +1/+1 counter on it.

Gix's Command

Choose two —
• Put two +1/+1 counters on up to one creature. It gains lifelink until end of turn.
• Destroy each creature with power 2 or less.
• Return up to two creature cards from your graveyard to your hand.
• Each opponent sacrifices a creature with the highest power among creatures they control.

Oblivion's Hunger

Target creature you control gains indestructible until end of turn. Draw a card if that creature has a +1/+1 counter on it. (Damage and effects that say "destroy" don't destroy the creature.)

Slum Reaper

When Slum Reaper enters the battlefield, each player sacrifices a creature.

Fain, the Broker

{T}, Sacrifice a creature: Put two +1/+1 counters on target creature.
{T}, Remove a counter from a creature you control: Create a Treasure token.
{T}, Sacrifice an artifact: Create a 2/1 white and black Inkling creature token with flying.
{3}{B}: Untap Fain, the Broker.

Grave Endeavor

Roll two d10 and choose one result. Return a creature card from your graveyard to the battlefield with a number of +1/+1 counters on it equal to that result. Then each opponent loses X life and you gain X life, where X is the other result.

Necromantic Summons

Put target creature card from a graveyard onto the battlefield under your control.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, that creature enters the battlefield with two additional +1/+1 counters on it.

Whisper, Blood Liturgist

{T}, Sacrifice two creatures: Return target creature card from your graveyard to the battlefield.

Unholy Indenture

Enchant creature
When enchanted creature dies, return that card to the battlefield under your control with a +1/+1 counter on it.

Fleshbag Marauder

When Fleshbag Marauder enters the battlefield, each player sacrifices a creature.

Woe Strider

When Woe Strider enters the battlefield, create a 0/1 white Goat creature token.
Sacrifice another creature: Scry 1.
Escape—{3}{B}{B}, Exile four other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)
Woe Strider escapes with two +1/+1 counters on it.

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Supernatural Stamina

Bloodtracker

Flying
{B}, Pay 2 life: Put a +1/+1 counter on Bloodtracker.
When Bloodtracker leaves the battlefield, draw a card for each +1/+1 counter on it.