Woe Strider

When Woe Strider enters, 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.

Nightscape Familiar

Blue spells and red spells you cast cost {1} less to cast.
{1}{B}: Regenerate Nightscape Familiar.

Ashnod's Altar

Viscera Seer

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

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Vengeful Bloodwitch

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

Whisper, Blood Liturgist

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

Zulaport Cutthroat

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

Warren Soultrader

Pay 1 life, Sacrifice another creature: Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Vampiric Rites

{1}{B}, Sacrifice a creature: You gain 1 life and draw a card.

Culling Dais

{T}, Sacrifice a creature: Put a charge counter on Culling Dais.
{1}, Sacrifice Culling Dais: Draw a card for each charge counter on Culling Dais.

Countersquall

Counter target noncreature spell. Its controller loses 2 life.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Sadistic Glee

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

Krav, the Unredeemed

Partner with Regna, the Redeemer (When this creature enters, target player may put Regna into their hand from their library, then shuffle.)
{B}, Sacrifice X creatures: Target player draws X cards and gains X life. Put X +1/+1 counters on Krav, the Unredeemed.

Pitiless Plunderer

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

Shivan Harvest

{1}{R}, Sacrifice a creature: Destroy target nonbasic land.

Attrition

{B}, Sacrifice a creature: Destroy target nonblack creature.

Hissing Iguanar

Whenever another creature dies, you may have Hissing Iguanar deal 1 damage to target player or planeswalker.

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.

Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Bastion of Remembrance

When Bastion of Remembrance 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.

Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

Shadows of the Past

Whenever a creature dies, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{4}{B}: Each opponent loses 2 life and you gain 2 life. Activate only if there are four or more creature cards in your graveyard.

Blade of the Bloodchief

Whenever a creature dies, put a +1/+1 counter on equipped creature. If equipped creature is a Vampire, put two +1/+1 counters on it instead.
Equip {1}

Blood Artist

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

Mystical Dispute

This spell costs {2} less to cast if it targets a blue spell.
Counter target spell unless its controller pays {3}.

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Negate

Corrupted Conviction

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Altar's Reap

Saw It Coming

Counter target spell.
Foretell {1}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Syr Konrad, the Grim

Whenever another creature dies, or a creature card is put into a graveyard from anywhere other than the battlefield, or a creature card leaves your graveyard, Syr Konrad, the Grim deals 1 damage to each opponent.
{1}{B}: Each player mills a card. (They each put the top card of their library into their graveyard.)

Tale's End

Counter target activated ability, triggered ability, or legendary spell.

Sauron, the Dark Lord

Ward—Sacrifice a legendary artifact or legendary creature.
Whenever an opponent casts a spell, amass Orcs 1.
Whenever an Army you control deals combat damage to a player, the Ring tempts you.
Whenever the Ring tempts you, you may discard your hand. If you do, draw four cards.

Vermin Gorger

{T}, Sacrifice another creature: Each opponent loses 2 life and you gain 2 life.

Reprocess

Sacrifice any number of artifacts, creatures, and/or lands. Draw a card for each permanent sacrificed this way.

Goblin Bombardment

Sacrifice a creature: Goblin Bombardment deals 1 damage to any target.

Mana Leak

Counter target spell unless its controller pays {3}.

Carrion Feeder

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

Razaketh, the Foulblooded

Flying, trample
Pay 2 life, Sacrifice another creature: Search your library for a card, put that card into your hand, then shuffle.

Village Rites

Exclude

Counter target creature spell.
Draw a card.

Morbid Opportunist

Whenever one or more other creatures die, draw a card. This ability triggers only once each turn.

Spell Crumple

Counter target spell. If that spell is countered this way, put it on the bottom of its owner's library instead of into that player's graveyard. Put Spell Crumple on the bottom of its owner's library.

Undercity Informer

{1}, Sacrifice a creature: Target player reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard.

Hell's Caretaker

{T}, Sacrifice a creature: Return target creature card from your graveyard to the battlefield. Activate only during your upkeep.

Blasting Station

{T}, Sacrifice a creature: Blasting Station deals 1 damage to any target.
Whenever a creature enters, you may untap Blasting Station.

Deathgreeter

Whenever another creature dies, you may gain 1 life.

Stubborn Denial

Counter target noncreature spell unless its controller pays {1}.
Ferocious — If you control a creature with power 4 or greater, counter that spell instead.

Counterspell

Sol Ring

Black Market

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

Doom Weaver

Reach
Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Doom Weaver is paired with another creature, each of those creatures has "When this creature dies, draw cards equal to its power."