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.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Defile

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

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.

Doom Whisperer

Flying, trample
Pay 2 life: Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Pact Weapon

As long as Pact Weapon is attached to a creature, you don't lose the game for having 0 or less life.
Whenever equipped creature attacks, draw a card and reveal it. The creature gets +X/+X until end of turn and you lose X life, where X is that card's mana value.
Equip—Discard a card.

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.

Dark Ritual

Arcane Signet

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

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

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.")

Charcoal Diamond

Charcoal Diamond enters tapped.
{T}: Add {B}.

Soul Kiss

Enchant creature
{B}, Pay 1 life: Enchanted creature gets +2/+2 until end of turn. Activate no more than three times each turn.

Corrupted Conviction

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

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

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.

Marionette Apprentice

Fabricate 1 (When this creature enters, put a +1/+1 counter on it or create a 1/1 colorless Servo artifact creature token.)
Whenever another creature or artifact you control is put into a graveyard from the battlefield, each opponent loses 1 life.

Swamp

Mask of Griselbrand

Equipped creature has flying and lifelink.
Whenever equipped creature dies, you may pay X life, where X is its power. If you do, draw X cards.
Equip {3}

Prowling Geistcatcher

Whenever you sacrifice another creature, exile it. If that creature was a token, put a +1/+1 counter on Prowling Geistcatcher.
When Prowling Geistcatcher leaves the battlefield, return each card exiled with it to the battlefield under your control.

Novice Occultist

When Novice Occultist dies, you draw a card and you lose 1 life.

Scorn-Blade Berserker

Backup 1 (When this creature enters, put a +1/+1 counter on target creature. If that's another creature, it gains the following ability until end of turn.)
{1}, Sacrifice this creature: Draw a card.

Phyrexian Processor

As Phyrexian Processor enters, pay any amount of life.
{4}, {T}: Create an X/X black Phyrexian Minion creature token, where X is the life paid as Phyrexian Processor entered.

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.)

Soul Channeling

Enchant creature
Pay 2 life: Regenerate enchanted creature.

Profane Transfusion

Two target players exchange life totals. You create an X/X colorless Horror artifact creature token, where X is the difference between those players' life totals.

Stromgald Cabal

{T}, Pay 1 life: Counter target white spell.

Consuming Corruption

Consuming Corruption deals X damage to target creature or planeswalker and you gain X life, where X is the number of Swamps you control.

Village Rites

K'rrik, Son of Yawgmoth

({B/P} can be paid with either {B} or 2 life.)
Lifelink
For each {B} in a cost, you may pay 2 life rather than pay that mana.
Whenever you cast a black spell, put a +1/+1 counter on K'rrik, Son of Yawgmoth.

Bitter Triumph

As an additional cost to cast this spell, discard a card or pay 3 life.
Destroy target creature or planeswalker.

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.)

Tenacious Underdog

Blitz—{2}{B}{B}, Pay 2 life. (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)
You may cast Tenacious Underdog from your graveyard using its blitz ability.

Grim Haruspex

Morph {B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
Whenever another nontoken creature you control dies, draw a card.

Xathrid Necromancer

Whenever Xathrid Necromancer or another Human creature you control dies, create a tapped 2/2 black Zombie creature token.

Assassin Initiate

{1}: Assassin Initiate gains your choice of flying, deathtouch, or lifelink until end of turn.

Village Cannibals

Whenever another Human creature dies, put a +1/+1 counter on Village Cannibals.

Go for the Throat

Greedy Freebooter

When Greedy Freebooter dies, scry 1 and create a Treasure token. (To scry 1, look at the top card of your library. You may put that card on the bottom. A Treasure token is an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Minion of the Wastes

Trample
As Minion of the Wastes enters, pay any amount of life.
Minion of the Wastes's power and toughness are each equal to the life paid as it entered.

Feed the Swarm

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

Souldrinker

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

Deepwood Ghoul

Disciple of Griselbrand

{1}, Sacrifice a creature: You gain life equal to the sacrificed creature's toughness.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Night's Whisper

Sol Ring

Sign in Blood

Target player draws two cards and loses 2 life.

Plaguecrafter

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

Unscrupulous Contractor

When Unscrupulous Contractor enters, you may sacrifice a creature. When you do, target player draws two cards and loses 2 life.
Plot {2}{B} (You may pay {2}{B} and exile this card from your hand. Cast it as a sorcery on a later turn without paying its mana cost. Plot only as a sorcery.)

Ophiomancer

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

Horn of Gondor

When Horn of Gondor enters, create a 1/1 white Human Soldier creature token.
{3}, {T}: Create X 1/1 white Human Soldier creature tokens, where X is the number of Humans you control.

Repay in Kind

Each player's life total becomes the lowest life total among all players.

Doomed Dissenter

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

Witch's Cottage

({T}: Add {B}.)
Witch's Cottage enters tapped unless you control three or more other Swamps.
When Witch's Cottage enters untapped, you may put target creature card from your graveyard on top of your library.

Phyrexian Vivisector

Whenever a creature you control dies, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Skirsdag High Priest

Morbid — {T}, Tap two untapped creatures you control: Create a 5/5 black Demon creature token with flying. Activate only if a creature died this turn.

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Carrion Howler

Pay 1 life: Carrion Howler gets +2/-1 until end of turn.

Mischievous Poltergeist

Flying
Pay 1 life: Regenerate Mischievous Poltergeist.

Greed

Font of Agonies

Whenever you pay life, put that many blood counters on Font of Agonies.
{1}{B}, Remove four blood counters from Font of Agonies: Destroy target creature.

Ormendahl, the Corrupter

Flying, trample, lifelink
Sacrifice another creature: Draw a card.

Jerren, Corrupted Bishop

Whenever Jerren, Corrupted Bishop enters or another nontoken Human you control dies, you lose 1 life and create a 1/1 white Human creature token.
{2}: Target Human you control gains lifelink until end of turn.
At the beginning of your end step, if you have exactly 13 life, you may pay {4}{B}{B}. If you do, transform Jerren.