Toxic Deluge

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

Thrull Wizard

{1}{B}: Counter target black spell unless that spell's controller pays {B} or {3}.

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."

Exsanguinate

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

Rogue's Passage

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

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.

Filth

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
As long as Filth is in your graveyard and you control a Swamp, creatures you control have swampwalk.

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}.

Baleful Mastery

You may pay {1}{B} rather than pay this spell's mana cost.
If the {1}{B} cost was paid, an opponent draws a card.
Exile target creature or planeswalker.

Stinging Study

You draw X cards and you lose X life, where X is the mana value of a commander you own on the battlefield or in the command zone.

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

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.

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.

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.

Caged Sun

As Caged Sun enters, choose a color.
Creatures you control of the chosen color get +1/+1.
Whenever a land's ability causes you to add one or more mana of the chosen color, add one additional mana of that color.

Bojuka Bog

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

Sign in Blood

Target player draws two cards and loses 2 life.

Expedition Map

{2}, {T}, Sacrifice this artifact: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Diabolic Tutor

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

Magus of the Coffers

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

Defile

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

Command Beacon

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

Reliquary Tower

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

Shizo, Death's Storehouse

{T}: Add {B}.
{B}, {T}: Target legendary creature gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)

Grim Tutor

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

Platinum Angel

Flying
You can't lose the game and your opponents can't win the game.

Vedalken Orrery

You may cast spells as though they had flash.

Arcane Signet

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

Liliana of the Dark Realms

+1: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.
−3: Target creature gets +X/+X or -X/-X until end of turn, where X is the number of Swamps you control.
−6: You get an emblem with "Swamps you control have '{T}: Add {B}{B}{B}{B}.'"

Syphon Mind

Each other player discards a card. You draw a card for each card discarded this way.

Demonic Tutor

Torment of Hailfire

Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent of their choice or discards a card.

Dark Ritual

Mutilate

All creatures get -1/-1 until end of turn for each Swamp you control.

Deadly Rollick

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

Cabal Stronghold

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

Sudden Spoiling

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Until end of turn, creatures target player controls lose all abilities and have base power and toughness 0/2.

Black Sun's Zenith

Put X -1/-1 counters on each creature. Shuffle Black Sun's Zenith into its owner's library.

Whispersilk Cloak

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

Insatiable Hemophage

Mutate {2}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Deathtouch
Whenever this creature mutates, each opponent loses X life and you gain X life, where X is the number of times this creature has mutated.

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.)

Lightning Greaves

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

Trailblazer's Boots

Equipped creature has nonbasic landwalk. (It can't be blocked as long as defending player controls a nonbasic land.)
Equip {2}

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.

Cabal Coffers

Feed the Swarm

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

Netherborn Altar

{T}, Put a soul counter on Netherborn Altar: Put your commander into your hand from the command zone. Then you lose 3 life for each soul counter on Netherborn Altar.

Force of Despair

If it's not your turn, you may exile a black card from your hand rather than pay this spell's mana cost.
Destroy all creatures that entered this turn.

Withering Boon

As an additional cost to cast this spell, pay 3 life.
Counter target creature spell.

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}.

Burnished Hart

{3}, Sacrifice this creature: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Night's Whisper

Jet Medallion

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

Sol Ring

Dirge Bat

Mutate {4}{B}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flash
Flying
Whenever this creature mutates, destroy target creature or planeswalker an opponent controls.

Chittering Harvester

Mutate {4}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, each opponent sacrifices a creature of their choice.

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.

Stunning Reversal

The next time you would lose the game this turn, instead draw seven cards and your life total becomes 1.
Exile Stunning Reversal.

Nirkana Revenant

Whenever you tap a Swamp for mana, add an additional {B}.
{B}: Nirkana Revenant gets +1/+1 until end of turn.

Infernal Grasp

Destroy target creature. You lose 2 life.

Vampiric Tutor

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

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.)

Torpor Orb

Creatures entering don't cause abilities to trigger.

Extraplanar Lens

Imprint — When Extraplanar Lens enters, you may exile target land you control.
Whenever a land with the same name as the exiled card is tapped for mana, its controller adds one mana of any type that land produced.

Sundial of the Infinite

{1}, {T}: End the turn. Activate only during your turn. (Exile all spells and abilities from the stack. Discard down to your maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.)

Phyrexian Obliterator

Trample
Whenever a source deals damage to Phyrexian Obliterator, that source's controller sacrifices that many permanents of their choice.

Bubbling Muck

Until end of turn, whenever a player taps a Swamp for mana, that player adds an additional {B}.

Snow-Covered Swamp

Mindleecher

Mutate {4}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flying
Whenever this creature mutates, exile the top card of each opponent's library face down. You may look at and play those cards for as long as they remain exiled.

Key to the City

{T}, Discard a card: Up to one target creature can't be blocked this turn.
Whenever Key to the City becomes untapped, you may pay {2}. If you do, draw a card.

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.)

Urborg, Tomb of Yawgmoth

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

Phyrexian Reclamation

{1}{B}, Pay 2 life: Return target creature card from your graveyard to your hand.

Cavern Whisperer

Mutate {3}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Menace (This creature can't be blocked except by two or more creatures.)
Whenever this creature mutates, each opponent discards a card.

Dauthi Embrace

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

Phyrexian Arena

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

Winding Canyons

{T}: Add {C}.
{2}, {T}: You may cast creature spells this turn as though they had flash.