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.

Whisper, Blood Liturgist

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

High Market

{T}: Add {C}.
{T}, Sacrifice a creature: You gain 1 life.

Village Rites

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

Deadly Rollick

If you control a commander, you may cast this spell without paying its mana cost.
Exile target creature.

Witch's Clinic

{T}: Add {C}.
{2}, {T}: Target commander gains lifelink until end of turn.

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.

Have

Serrated Scorpion

When Serrated Scorpion dies, it deals 2 damage to each opponent and you gain 2 life.

Don't Have

Morbid Opportunist

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

Accursed Marauder

When Accursed Marauder enters, each player sacrifices a nontoken creature of their choice.

Consuming Sepulcher

At the beginning of your upkeep, each opponent loses 1 life and you gain 1 life.

Tithing Blade

When Tithing Blade enters, each opponent sacrifices a creature of their choice.
Craft with creature {4}{B} ({4}{B}, Exile this artifact, Exile a creature you control or a creature card from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

Tithing Blade // Consuming Sepulcher

Sign in Blood

Target player draws two cards and loses 2 life.

Ashnod's Altar

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}

Sangromancer

Flying
Whenever a creature an opponent controls dies, you may gain 3 life.
Whenever an opponent discards a card, you may gain 3 life.

Vraan, Executioner Thane

Whenever one or more other creatures you control die, each opponent loses 2 life and you gain 2 life. This ability triggers only once each turn.

Fleshbag Marauder

When Fleshbag Marauder enters, each player sacrifices a creature of their choice.

Return to Action

Until end of turn, target creature gets +1/+0 and gains lifelink and "When this creature dies, return it to the battlefield tapped under its owner's control."

Drivnod, Carnage Dominus

If a creature dying causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
{B/P}{B/P}, Exile three creature cards from your graveyard: Put an indestructible counter on Drivnod, Carnage Dominus. ({B/P} can be paid with either {B} or 2 life.)

Lord Skitter, Sewer King

Whenever another Rat you control enters, exile up to one target card from an opponent's graveyard.
At the beginning of combat on your turn, create a 1/1 black Rat creature token with "This creature can't block."

Sheoldred's Edict

Choose one —
• Each opponent sacrifices a nontoken creature of their choice.
• Each opponent sacrifices a creature token of their choice.
• Each opponent sacrifices a planeswalker of their choice.

Bloodsoaked Champion

Bloodsoaked Champion can't block.
Raid — {1}{B}: Return Bloodsoaked Champion from your graveyard to the battlefield. Activate only if you attacked this turn.

Sadistic Glee

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

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

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.)

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

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.)

Dictate of Erebos

Flash
Whenever a creature you control dies, each opponent sacrifices a creature of their choice.

Revel in Riches

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

Dauthi Embrace

{B}{B}: Target creature gains shadow until end of turn. (It can block or be blocked by only creatures with shadow.)

Liliana's Talent

Enchant planeswalker
Enchanted planeswalker has "[−8]: Put all creature cards from all graveyards onto the battlefield under your control."
Whenever a creature deals damage to enchanted planeswalker, destroy that creature.

Spark Harvest

As an additional cost to cast this spell, sacrifice a creature or pay {3}{B}.
Destroy target creature or planeswalker.

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.")

Crypt Ghast

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever you tap a Swamp for mana, add an additional {B}.

Tragic Slip

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.

Malakir Mire

Malakir Mire enters tapped.
{T}: Add {B}.

Malakir Rebirth

Choose target creature. You lose 2 life. Until end of turn, that creature gains "When this creature dies, return it to the battlefield tapped under its owner's control."

Malakir Rebirth // Malakir Mire

Bone Splinters

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

Cover of Darkness

As Cover of Darkness enters, choose a creature type.
Creatures of the chosen type have fear. (They can't be blocked except by artifact creatures and/or black creatures.)

Greed

Ghoulish Procession

Whenever one or more nontoken creatures die, create a 2/2 black Zombie creature token with decayed. This ability triggers only once each turn. (A creature with decayed can't block. When it attacks, sacrifice it at end of combat.)

Tainted Strike

Target creature gets +1/+0 and gains infect until end of turn. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Ravenous Chupacabra

When Ravenous Chupacabra enters, destroy target creature an opponent controls.

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}

Fake Your Own Death

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

Maze of Ith

{T}: Untap target attacking creature. Prevent all combat damage that would be dealt to and dealt by that creature this turn.

Read the Bones

Scry 2, then draw two cards. You lose 2 life. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Annihilating Glare

As an additional cost to cast this spell, pay {4} or sacrifice an artifact or creature.
Destroy target creature or planeswalker.

Whispersilk Cloak

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

Tevesh Szat, Doom of Fools

+2: Create two 0/1 black Thrull creature tokens.
+1: You may sacrifice another creature or planeswalker. If you do, draw two cards, then draw another card if the sacrificed permanent was a commander.
−10: Gain control of all commanders. Put all commanders from the command zone onto the battlefield under your control.
Tevesh Szat, Doom of Fools can be your commander.
Partner

Corrupted Conviction

Ophiomancer

At the beginning of each upkeep, if you control no Snakes, create a 1/1 black Snake creature token with deathtouch.

Kaya's Ghostform

Enchant creature or planeswalker you control
When enchanted permanent dies or is put into exile, return that card to the battlefield under your control.

Massacre Girl

Menace
When Massacre Girl enters, each other creature gets -1/-1 until end of turn. Whenever a creature dies this turn, each creature other than Massacre Girl gets -1/-1 until end of turn.

Grave Pact

Whenever a creature you control dies, each other player sacrifices a creature of their choice.

Sengir, the Dark Baron

Flying
Whenever another creature dies, put two +1/+1 counters on Sengir, the Dark Baron.
Whenever another player loses the game, you gain life equal to that player's life total as the turn began.
Partner (You can have two commanders if both have partner.)

Merciless Executioner

When Merciless Executioner enters, each player sacrifices a creature of their choice.

Falkenrath Noble

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

Cabal Ritual

Add {B}{B}{B}.
Threshold — Add {B}{B}{B}{B}{B} instead if seven or more cards are in your graveyard.

Jadar, Ghoulcaller of Nephalia

At the beginning of your end step, if you control no creatures with decayed, create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)

Bloodghast

Bloodghast can't block.
Bloodghast has haste as long as an opponent has 10 or less life.
Landfall — Whenever a land you control enters, you may return Bloodghast from your graveyard to the battlefield.

Plaguecrafter

When Plaguecrafter enters, each player sacrifices a creature or planeswalker of their choice. Each player who can't discards a card.

Diabolic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Ogre Slumlord

Whenever another nontoken creature dies, you may create a 1/1 black Rat creature token.
Rats you control have deathtouch.

Blood Artist

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

Profane Tutor

Suspend 2—{1}{B} (Rather than cast this card from your hand, pay {1}{B} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
Search your library for a card, put that card into your hand, then shuffle.

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.

Nim Deathmantle

Equipped creature gets +2/+2, has intimidate, and is a black Zombie. (A creature with intimidate can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Whenever a nontoken creature is put into your graveyard from the battlefield, you may pay {4}. If you do, return that card to the battlefield and attach Nim Deathmantle to it.
Equip {4}

Victimize

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

Nether Traitor

Haste
Shadow (This creature can block or be blocked by only creatures with shadow.)
Whenever another creature is put into your graveyard from the battlefield, you may pay {B}. If you do, return Nether Traitor from your graveyard to the battlefield.

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.")

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Undying Malice

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."

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 of their choice that shares a card type with it. For each opponent who doesn't, that player loses 2 life and you draw a card.

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.

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Body Count

Spectacle {B} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Draw a card for each creature that died under your control this turn.

Command Beacon

{T}: Add {C}.
{T}, Sacrifice Command Beacon: Put your commander into your hand from the command zone.

Doom Blade

Zulaport Cutthroat

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

Butcher of Malakir

Flying
Whenever Butcher of Malakir or another creature you control dies, each opponent sacrifices a creature of their choice.

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.

Cast Down

Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Jet Medallion

Black spells you cast cost {1} less to cast.

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.

Vein Ripper

Flying
Ward—Sacrifice a creature.
Whenever a creature dies, target opponent loses 2 life and you gain 2 life.

Sol Ring

Dark Ritual

Szat's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Each opponent sacrifices a creature they control with the greatest power.
• Exile all opponents' graveyards, then create X 0/1 black Thrull creature tokens, where X is the greatest power among creature cards exiled this way.

Reassembling Skeleton

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

Innocent Blood

Each player sacrifices a creature of their choice.

Swamp

Indulgent Tormentor

Flying
At the beginning of your upkeep, draw a card unless target opponent sacrifices a creature of their choice or pays 3 life.

Diabolic Intent

As an additional cost to cast this spell, sacrifice a creature.
Search your library for a card, put that card into your hand, then shuffle.

Forsaken Miner

Forsaken Miner can't block.
Whenever you commit a crime, you may pay {B}. If you do, return Forsaken Miner from your graveyard to the battlefield. (Targeting opponents, anything they control, and/or cards in their graveyards is a crime.)

Beseech the Mirror

Bargain (You may sacrifice an artifact, enchantment, or token as you cast this spell.)
Search your library for a card, exile it face down, then shuffle. If this spell was bargained, you may cast the exiled card without paying its mana cost if that spell's mana value is 4 or less. Put the exiled card into your hand if it wasn't cast this way.

Endrek Sahr, Master Breeder

Whenever you cast a creature spell, create X 1/1 black Thrull creature tokens, where X is that spell's mana value.
When you control seven or more Thrulls, sacrifice Endrek Sahr, Master Breeder.

Deadly Tempest

Destroy all creatures. Each player loses life equal to the number of creatures they controlled that were destroyed this way.

Mortuary Mire

Mortuary Mire enters tapped.
When Mortuary Mire enters, you may put target creature card from your graveyard on top of your library.
{T}: Add {B}.