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.)

Castle Locthwain

Castle Locthwain enters tapped unless you control a Swamp.
{T}: Add {B}.
{1}{B}{B}, {T}: Draw a card, then you lose life equal to the number of cards in your hand.

Mercenary Knight

When Mercenary Knight enters, sacrifice it unless you discard a creature card.

Nameless Inversion

Changeling (This card is every creature type.)
Target creature gets +3/-3 and loses all creature types until end of turn.

Rathi Intimidator

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
{2}, {T}: Search your library for a Mercenary permanent card with mana value 2 or less, put it onto the battlefield, then shuffle.

Spineless Thug

Bog Smugglers

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Endless Whispers

Each creature has "When this creature dies, choose target opponent. That player puts this card from its owner's graveyard onto the battlefield under their control at the beginning of the next end step."

Staff of the Death Magus

Whenever you cast a black spell or a Swamp you control enters, you gain 1 life.

Snow-Covered Swamp

The Cauldron of Eternity

This spell costs {2} less to cast for each creature card in your graveyard.
Whenever a creature you control dies, put it on the bottom of its owner's library.
{2}{B}, {T}, Pay 2 life: Return target creature card from your graveyard to the battlefield. Activate only as a sorcery.

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.

Rebel Informer

Rebel Informer can't be the target of white spells or abilities from white sources.
{3}: Put target nontoken Rebel on the bottom of its owner's library.

Death Charmer

Whenever Death Charmer deals combat damage to a creature, that creature's controller loses 2 life unless they pay {2}.

Doomed Necromancer

{B}, {T}, Sacrifice Doomed Necromancer: Return target creature card from your graveyard to the battlefield.

Ascendant Evincar

Flying (This creature can't be blocked except by creatures with flying or reach.)
Other black creatures get +1/+1.
Nonblack creatures get -1/-1.

Graveshifter

Changeling (This card is every creature type.)
When Graveshifter enters, you may return target creature card from your graveyard to your hand.

Sol Ring

Spiteful Bully

At the beginning of your upkeep, Spiteful Bully deals 3 damage to target creature you control.

Demon's Horn

Whenever a player casts a black spell, you may gain 1 life.

Strongarm Thug

When Strongarm Thug enters, you may return target Mercenary card from your graveyard to your hand.

Agent of Shauku

{1}{B}, Sacrifice a land: Target creature gets +2/+0 until end of turn.

Skulking Fugitive

When Skulking Fugitive becomes the target of a spell or ability, sacrifice it.

Cateran Summons

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

Primeval Shambler

{B}: Primeval Shambler gets +1/+1 until end of turn.

Highway Robber

When Highway Robber enters, target opponent loses 2 life and you gain 2 life.

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.

Molting Harpy

Flying
At the beginning of your upkeep, sacrifice Molting Harpy unless you pay {2}.

Cateran Persuader

{1}, {T}: Search your library for a Mercenary permanent card with mana value 1 or less, put it onto the battlefield, then shuffle.

Urborg, Tomb of Yawgmoth

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

Worn Powerstone

Worn Powerstone enters tapped.
{T}: Add {C}{C}.

Phyrexian Prowler

Fading 3 (This creature enters with three fade counters on it. At the beginning of your upkeep, remove a fade counter from it. If you can't, sacrifice it.)
Remove a fade counter from Phyrexian Prowler: Phyrexian Prowler gets +1/+1 until end of turn.

Thought Vessel

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

Strionic Resonator

{2}, {T}: Copy target triggered ability you control. You may choose new targets for the copy. (A triggered ability uses the words "when," "whenever," or "at.")

Ayara, First of Locthwain

Whenever Ayara, First of Locthwain or another black creature you control enters, each opponent loses 1 life and you gain 1 life.
{T}, Sacrifice another black creature: Draw a card.

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}.

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.

Cateran Overlord

Sacrifice a creature: Regenerate Cateran Overlord.
{6}, {T}: Search your library for a Mercenary permanent card with mana value 6 or less, put it onto the battlefield, then shuffle.

Jet Medallion

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

Charcoal Diamond

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

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.)

Rathi Fiend

When Rathi Fiend enters, each player loses 3 life.
{3}, {T}: Search your library for a Mercenary permanent card with mana value 3 or less, put it onto the battlefield, then shuffle.

Cateran Slaver

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
{5}, {T}: Search your library for a Mercenary permanent card with mana value 5 or less, put it onto the battlefield, then shuffle.

Dauthi Mercenary

Shadow (This creature can block or be blocked by only creatures with shadow.)
{1}{B}: Dauthi Mercenary gets +1/+0 until end of turn.

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.

Cateran Enforcer

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
{4}, {T}: Search your library for a Mercenary permanent card with mana value 4 or less, put it onto the battlefield, then shuffle.

Phyrexian Driver

When Phyrexian Driver enters, other Mercenary creatures get +1/+1 until end of turn.

Misshapen Fiend

Gate to Phyrexia

Sacrifice a creature: Destroy target artifact. Activate only during your upkeep and only once each turn.

Pit Raptor

Flying, first strike
At the beginning of your upkeep, sacrifice Pit Raptor unless you pay {2}{B}{B}.

Alley Grifters

Whenever Alley Grifters becomes blocked, defending player discards a card.

Rampart Crawler

Rampart Crawler can't be blocked by Walls.

Bog Glider

Flying
{T}, Sacrifice a land: Search your library for a Mercenary permanent card with mana value 2 or less, put it onto the battlefield, then shuffle.

Cateran Kidnappers

{3}, {T}: Search your library for a Mercenary permanent card with mana value 3 or less, put it onto the battlefield, then shuffle.

Basalt Monolith

Basalt Monolith doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{3}: Untap Basalt Monolith.

Sign in Blood

Target player draws two cards and loses 2 life.

Phage the Untouchable

When Phage the Untouchable enters, if you didn't cast it from your hand, you lose the game.
Whenever Phage deals combat damage to a creature, destroy that creature. It can't be regenerated.
Whenever Phage deals combat damage to a player, that player loses the game.

Rathi Assassin

{1}{B}{B}, {T}: Destroy target tapped nonblack creature.
{3}, {T}: Search your library for a Mercenary permanent card with mana value 3 or less, put it onto the battlefield, then shuffle.

Cairn Wanderer

Changeling (This card is every creature type.)
As long as a creature card with flying is in a graveyard, Cairn Wanderer has flying. The same is true for fear, first strike, double strike, deathtouch, haste, landwalk, lifelink, protection, reach, trample, shroud, and vigilance.

Everflowing Chalice

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
Everflowing Chalice enters with a charge counter on it for each time it was kicked.
{T}: Add {C} for each charge counter on Everflowing Chalice.

Cabal Coffers

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

Silent Assassin

{3}{B}: Destroy target blocking creature at end of combat.

Phyrexian Arena

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

Read the Bones

Scry 2, then draw two cards. You lose 2 life.

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.

Blood Celebrant

{B}, Pay 1 life: 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.)

Cateran Brute

{2}, {T}: Search your library for a Mercenary permanent card with mana value 2 or less, put it onto the battlefield, then shuffle.

Crypt of Agadeem

Crypt of Agadeem enters tapped.
{T}: Add {B}.
{2}, {T}: Add {B} for each black creature card in your graveyard.