Yahenni, Undying Partisan

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

Ashes of the Abhorrent

Players can't cast spells from graveyards or activate abilities of cards in graveyards.
Whenever a creature dies, you gain 1 life.

Teysa Karlov

If a creature dying causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
Creature tokens you control have vigilance and lifelink.

Deathbloom Thallid

When this creature dies, create a 1/1 green Saproling creature token.

Doomed Traveler

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

Martyr of Dusk

When this creature dies, create a 1/1 white Vampire creature token with lifelink.

Dead Man's Chest

Enchant creature an opponent controls
When enchanted creature dies, exile cards equal to its power from the top of its owner's library. You may cast spells from among those cards for as long as they remain exiled, and mana of any type can be spent to cast them.

Disentomb

Return target creature card from your graveyard to your hand.

Desperate Sentry

When this creature dies, create a 3/2 colorless Eldrazi Horror creature token.
Delirium — This creature gets +3/+0 as long as there are four or more card types among cards in your graveyard.

Witch's Oven

{T}, Sacrifice a creature: Create a Food token. If the sacrificed creature's toughness was 4 or greater, create two Food tokens instead. (They're artifacts with "{2}, {T}, Sacrifice this token: You gain 3 life.")

Priest of Forgotten Gods

{T}, Sacrifice two other creatures: Any number of target players each lose 2 life and sacrifice a creature of their choice. You add {B}{B} and draw a card.

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.

Cast Down

Zulaport Cutthroat

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

Malefic Scythe

This Equipment enters with a soul counter on it.
Equipped creature gets +1/+1 for each soul counter on this Equipment.
Whenever equipped creature dies, put a soul counter on this Equipment.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Luminous Broodmoth

Flying
Whenever a creature you control without flying dies, return it to the battlefield under its owner's control with a flying counter on it.

Gavony Unhallowed

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

Swamp

Mace of the Valiant

Equipped creature gets +1/+1 for each charge counter on this Equipment and has vigilance. (Attacking doesn't cause it to tap.)
Whenever a creature you control enters, put a charge counter on this Equipment.
Equip {3}

Tattered Mummy

When this creature dies, each opponent loses 2 life.

Doom Foretold

At the beginning of each player's upkeep, that player sacrifices a nonland, nontoken permanent of their choice. If that player can't, they discard a card, they lose 2 life, you draw a card, you gain 2 life, you create a 2/2 white Knight creature token with vigilance, then you sacrifice this enchantment.

Lawless Broker

When this creature dies, put a +1/+1 counter on target creature you control.

Demon of Dark Schemes

Flying
When this creature enters, all other creatures get -2/-2 until end of turn.
Whenever another creature dies, you get {E} (an energy counter).
{2}{B}, Pay {E}{E}{E}{E}: Put target creature card from a graveyard onto the battlefield under your control tapped.

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Quest for the Gravelord

Whenever a creature dies, you may put a quest counter on this enchantment.
Remove three quest counters from this enchantment and sacrifice it: Create a 5/5 black Zombie Giant creature token.

Open the Graves

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

Serrated Scorpion

When this creature dies, it deals 2 damage to each opponent and you gain 2 life.

Screeching Buzzard

Flying
When this creature dies, each opponent discards a card.

Thallid Soothsayer

Paladin of Atonement

At the beginning of each upkeep, if you lost life last turn, put a +1/+1 counter on this creature.
When this creature dies, you gain life equal to its toughness.

Midnight Reaper

Whenever a nontoken creature you control dies, this creature deals 1 damage to you and you draw a card.

Basri's Lieutenant

Vigilance, protection from multicolored
When this creature enters, put a +1/+1 counter on target creature you control.
Whenever this creature or another creature you control dies, if it had a +1/+1 counter on it, create a 2/2 white Knight creature token with vigilance.

Unruly Mob

Soul Salvage

Return up to two target creature cards from your graveyard to your hand.

Revenge of Ravens

Whenever a creature attacks you or a planeswalker you control, that creature's controller loses 1 life and you gain 1 life.

Bastion of Remembrance

When this enchantment enters, 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.

Unbreakable Formation

Creatures you control gain indestructible until end of turn.
Addendum — If you cast this spell during your main phase, put a +1/+1 counter on each of those creatures and they gain vigilance until end of turn.

Pitiless Plunderer

Whenever another creature you control dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Bounty Agent

Vigilance
{T}, Sacrifice this creature: Destroy target legendary permanent that's an artifact, creature, or enchantment.

Garrison Cat

When this creature dies, create a 1/1 white Human Soldier creature token.

Mausoleum Harpy

Flying
Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
Whenever another creature you control dies, if you have the city's blessing, put a +1/+1 counter on this creature.

Bone Splinters

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

Invoke the Divine

Destroy target artifact or enchantment. You gain 4 life.

Revel in Riches

Whenever a creature an opponent controls dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
At the beginning of your upkeep, if you control ten or more Treasures, you win the game.

Plains

Swarm of Bloodflies

Flying
This creature enters with two +1/+1 counters on it.
Whenever another creature dies, put a +1/+1 counter on this creature.

True Love's Kiss

Exile target artifact or enchantment.
Draw a card.

Take Vengeance

Doomed Dissenter

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

Baird, Steward of Argive

Vigilance
Creatures can't attack you or planeswalkers you control unless their controller pays {1} for each of those creatures.

Filigree Familiar

When this creature enters, you gain 2 life.
When this creature dies, draw a card.

Dire Fleet Hoarder

When this creature dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")