Pontiff of Blight

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.)
Other creatures you control have extort. (If a creature has multiple instances of extort, each triggers separately.)

Sheoldred, the Apocalypse

Deathtouch
Whenever you draw a card, you gain 2 life.
Whenever an opponent draws a card, they lose 2 life.

Sol Ring

Entomb

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

Vile Entomber

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When this creature enters, search your library for a card, put that card into your graveyard, then shuffle.

Asmodeus the Archfiend

Binding Contract — If you would draw a card, exile the top card of your library face down instead.
{B}{B}{B}: Draw seven cards.
{B}: Return all cards exiled with Asmodeus the Archfiend to their owner's hand and you lose that much life.

Dauthi Voidwalker

Shadow (This creature can block or be blocked by only creatures with shadow.)
If a card would be put into an opponent's graveyard from anywhere, instead exile it with a void counter on it.
{T}, Sacrifice Dauthi Voidwalker: Choose an exiled card an opponent owns with a void counter on it. You may play it this turn without paying its mana cost.

Phyrexian Arena

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

Mind Stone

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

Bolas's Citadel

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

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.)

Imp's Mischief

Change the target of target spell with a single target. You lose life equal to that spell's mana value.

Swamp

Necropotence

Skip your draw step.
Whenever you discard a card, exile that card from your graveyard.
Pay 1 life: Exile the top card of your library face down. Put that card into your hand at the beginning of your next end step.

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

Diabolic Tutor

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

Sanguine Bond

Whenever you gain life, target opponent loses that much life.

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}.

Arcane Signet

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

Beseech the Queen

({2/B} can be paid with any two mana or with {B}. This card's mana value is 6.)
Search your library for a card with mana value less than or equal to the number of lands you control, reveal it, put it into your hand, then shuffle.

Buried Alive

Search your library for up to three creature cards, put them into your graveyard, then shuffle.

Dimir House Guard

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Sacrifice a creature: Regenerate Dimir House Guard.
Transmute {1}{B}{B} ({1}{B}{B}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Defile

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

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.
{T}: Add {C}{C}.

Cabal Ritual

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

Animate Dead

Enchant creature card in a graveyard
When Animate Dead enters, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Animate Dead." Return enchanted creature card to the battlefield under your control and attach Animate Dead to it. When Animate Dead leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets -1/-0.

Blood Pet

Bontu's Monument

Black creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, each opponent loses 1 life and you gain 1 life.

Aetherflux Reservoir

Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.
Pay 50 life: Aetherflux Reservoir deals 50 damage to any target.

Reliquary Tower

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

Professor Onyx

Magecraft — Whenever you cast or copy an instant or sorcery spell, each opponent loses 2 life and you gain 2 life.
+1: You lose 1 life. Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.
−3: Each opponent sacrifices a creature with the greatest power among creatures that player controls.
−8: Each opponent may discard a card. If they don't, they lose 3 life. Repeat this process six more times.

Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

Skirge Familiar

Demonic Tutor

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Peer into the Abyss

Target player draws cards equal to half the number of cards in their library and loses half their life. Round up each time.

Vein Ripper

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

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.

Dread Presence

Whenever a Swamp you control enters, choose one —
• You draw a card and you lose 1 life.
• Dread Presence deals 2 damage to any target and you gain 2 life.

Orcish Bowmasters

Flash
When Orcish Bowmasters enters and whenever an opponent draws a card except the first one they draw in each of their draw steps, Orcish Bowmasters deals 1 damage to any target. Then amass Orcs 1.

Bitter Triumph

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

Dark Petition

Search your library for a card, put that card into your hand, then shuffle.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, add {B}{B}{B}.

Hoarding Broodlord

Convoke
Flying
When Hoarding Broodlord enters, search your library for a card, exile it face down, then shuffle. For as long as that card remains exiled, you may play it.
Spells you cast from exile have convoke.

Feed the Swarm

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

Exquisite Blood

Whenever an opponent loses life, you gain that much life.

Bloodletter of Aclazotz

Flying
If an opponent would lose life during your turn, they lose twice that much life instead. (Damage causes loss of life.)

Deadly Rollick

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

Mana Vault

Mana Vault doesn't untap during your untap step.
At the beginning of your upkeep, you may pay {4}. If you do, untap Mana Vault.
At the beginning of your draw step, if Mana Vault is tapped, it deals 1 damage to you.
{T}: Add {C}{C}{C}.

Cut Down

Destroy target creature with total power and toughness 5 or less.

Sensei's Divining Top

{1}: Look at the top three cards of your library, then put them back in any order.
{T}: Draw a card, then put Sensei's Divining Top on top of its owner's library.

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to its mana value.

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Chainer, Dementia Master

All Nightmares get +1/+1.
{B}{B}{B}, Pay 3 life: Put target creature card from a graveyard onto the battlefield under your control. That creature is black and is a Nightmare in addition to its other creature types.
When Chainer, Dementia Master leaves the battlefield, exile all Nightmares.

Insatiable Avarice

Spree (Choose one or more additional costs.)
+ {2} — Search your library for a card, then shuffle and put that card on top.
+ {B}{B} — Target player draws three cards and loses 3 life.

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Grim Tutor

Search your library for a card, put that card into your hand, then shuffle. You lose 3 life.

Shard of the Nightbringer

Flying
Drain Life — When Shard of the Nightbringer enters, if you cast it, target opponent loses half their life, rounded up. You gain life equal to the life lost this way.

Cabal Stronghold

{T}: Add {C}.
{3}, {T}: Add {B} for each basic Swamp you control.

Vilis, Broker of Blood

Flying
{B}, Pay 2 life: Target creature gets -1/-1 until end of turn.
Whenever you lose life, draw that many cards. (Damage causes loss of life.)

Vito, Thorn of the Dusk Rose

Whenever you gain life, target opponent loses that much life.
{3}{B}{B}: Creatures you control gain lifelink until end of turn.

Sign in Blood

Target player draws two cards and loses 2 life.

Long Goodbye

This spell can't be countered. (This includes by the ward ability.)
Destroy target creature or planeswalker with mana value 3 or less.

Jet Medallion

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

Greed

Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

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.

Jeweled Lotus

{T}, Sacrifice Jeweled Lotus: Add three mana of any one color. Spend this mana only to cast your commander.

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.

Opposition Agent

Flash
You control your opponents while they're searching their libraries.
While an opponent is searching their library, they exile each card they find. You may play those cards for as long as they remain exiled, and you may spend mana as though it were mana of any color to cast them.

Necrotic Ooze

As long as Necrotic Ooze is on the battlefield, it has all activated abilities of all creature cards in all graveyards.

Dark Ritual

Toxic Deluge

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

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.)