Urborg, Tomb of Yawgmoth

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

Arcane Signet

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

Iron Maiden

At the beginning of each opponent's upkeep, Iron Maiden deals X damage to that player, where X is the number of cards in their hand minus 4.

Zenith Chronicler

Whenever a player casts their first multicolored spell each turn, each other player draws a card.

Horn of Greed

Whenever a player plays a land, that player draws a card.

Reliquary Tower

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

Fell Specter

Flying
When Fell Specter enters, target opponent discards a card.
Whenever an opponent discards a card, that player loses 2 life.

Howling Mine

At the beginning of each player's draw step, if Howling Mine is untapped, that player draws an additional card.

Sphere of Resistance

Temple Bell

Doom Blade

Ob Nixilis, the Hate-Twisted

Whenever an opponent draws a card, Ob Nixilis, the Hate-Twisted deals 1 damage to that player.
−2: Destroy target creature. Its controller draws two cards.

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.

Jet Medallion

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

Master of the Feast

Flying
At the beginning of your upkeep, each opponent draws a card.

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.

Damping Sphere

If a land is tapped for two or more mana, it produces {C} instead of any other type and amount.
Each spell a player casts costs {1} more to cast for each other spell that player has cast this turn.

Silent Arbiter

No more than one creature can attack each combat.
No more than one creature can block each combat.

Seizan, Perverter of Truth

At the beginning of each player's upkeep, that player loses 2 life and draws two cards.

The Meathook Massacre

When The Meathook Massacre enters, each creature gets -X/-X until end of turn.
Whenever a creature you control dies, each opponent loses 1 life.
Whenever a creature an opponent controls dies, you gain 1 life.

Underworld Dreams

Whenever an opponent draws a card, Underworld Dreams deals 1 damage to that player.

Kagemaro, First to Suffer

Kagemaro, First to Suffer's power and toughness are each equal to the number of cards in your hand.
{B}, Sacrifice Kagemaro: All creatures get -X/-X until end of turn, where X is the number of cards in your hand.

Nightmare Unmaking

Choose one —
• Exile each creature with power greater than the number of cards in your hand.
• Exile each creature with power less than the number of cards in your hand.

Cabal 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.

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.

Font of Mythos

At the beginning of each player's draw step, that player draws two additional cards.

Sign in Blood

Target player draws two cards and loses 2 life.

Mind Stone

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

Toxic Deluge

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

Grafdigger's Cage

Creature cards in graveyards and libraries can't enter the battlefield.
Players can't cast spells from graveyards or libraries.

Howling Golem

Whenever Howling Golem attacks or blocks, each player draws a card.

Swamp

Bojuka Bog

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

Coveted Jewel

When Coveted Jewel enters, draw three cards.
{T}: Add three mana of any one color.
Whenever one or more creatures an opponent controls attack you and aren't blocked, that player draws three cards and gains control of Coveted Jewel. Untap it.

Deadly Rollick

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

Field of Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice Field of Ruin: Destroy target nonbasic land an opponent controls. Each player searches their library for a basic land card, puts it onto the battlefield, then shuffles.

No Mercy

Whenever a creature deals damage to you, destroy it.

Geier Reach Sanitarium

{T}: Add {C}.
{2}, {T}: Each player draws a card, then discards a card.

Bloodchief Ascension

At the beginning of each end step, if an opponent lost 2 or more life this turn, you may put a quest counter on Bloodchief Ascension. (Damage causes loss of life.)
Whenever a card is put into an opponent's graveyard from anywhere, if Bloodchief Ascension has three or more quest counters on it, you may have that player lose 2 life. If you do, you gain 2 life.

Mikokoro, Center of the Sea

{T}: Add {C}.
{2}, {T}: Each player draws a card.

Damnation

Destroy all creatures. They can't be regenerated.

Darkness

Prevent all combat damage that would be dealt this turn.

Price of Knowledge

Players have no maximum hand size.
At the beginning of each opponent's upkeep, Price of Knowledge deals damage to that player equal to the number of cards in that player's hand.

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.)

Rankle, Master of Pranks

Flying, haste
Whenever Rankle, Master of Pranks deals combat damage to a player, choose any number —
• Each player discards a card.
• Each player loses 1 life and draws a card.
• Each player sacrifices a creature.

Thought Vessel

Megrim

Whenever an opponent discards a card, Megrim deals 2 damage to that player.

Withering Boon

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

Nightmarish End

Target creature gets -X/-X until end of turn, where X is the number of cards in your hand.

V.A.T.S.

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Choose any number of target creatures with equal toughness. Destroy the chosen creatures.

Blood Pact

Mutilate

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

Heartless Act

Choose one —
• Destroy target creature with no counters on it.
• Remove up to three counters from target creature.

Ebony Owl Netsuke

At the beginning of each opponent's upkeep, if that player has seven or more cards in hand, Ebony Owl Netsuke deals 4 damage to that player.

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

Thorn of Amethyst

Noncreature spells cost {1} more to cast.

Fellwar Stone

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

Sol Ring

Syphon Mind

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

Runed Servitor

When Runed Servitor dies, each player draws a card.

Viseling

At the beginning of each opponent's upkeep, Viseling deals X damage to that player, where X is the number of cards in their hand minus 4.

Snuff Out

If you control a Swamp, you may pay 4 life rather than pay this spell's mana cost.
Destroy target nonblack creature. It can't be regenerated.

Liliana's Caress

Whenever an opponent discards a card, that player loses 2 life.

Sheoldred, the Apocalypse

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

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.)

Fate Unraveler

Whenever an opponent draws a card, Fate Unraveler deals 1 damage to that player.

Thespian's Stage

{T}: Add {C}.
{2}, {T}: Thespian's Stage becomes a copy of target land, except it has this ability.

Black Vise

As Black Vise enters, choose an opponent.
At the beginning of the chosen player's upkeep, Black Vise deals X damage to that player, where X is the number of cards in their hand minus 4.

Waste Not

Whenever an opponent discards a creature card, create a 2/2 black Zombie creature token.
Whenever an opponent discards a land card, add {B}{B}.
Whenever an opponent discards a noncreature, nonland card, draw a card.

Otherworld Atlas

{T}: Put a charge counter on Otherworld Atlas.
{T}: Each player draws a card for each charge counter on Otherworld Atlas.

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.