Have

Toxrill, the Corrosive

At the beginning of each end step, put a slime counter on each creature you don't control.
Creatures you don't control get -1/-1 for each slime counter on them.
Whenever a creature you don't control with a slime counter on it dies, create a 1/1 black Slug creature token.
{U}{B}, Sacrifice a Slug: Draw a card.

Choked Estuary

As Choked Estuary enters, you may reveal an Island or Swamp card from your hand. If you don't, Choked Estuary enters tapped.
{T}: Add {U} or {B}.

Polymorphist's Jest

Until end of turn, each creature target player controls loses all abilities and becomes a blue Frog with base power and toughness 1/1.

Feign Death

Until end of turn, target creature gains "When this creature dies, return it to the battlefield tapped under its owner's control with a +1/+1 counter on it."

Needs Attention

High Tide

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

Nest of Scarabs

Whenever you put one or more -1/-1 counters on a creature, create that many 1/1 black Insect creature tokens.

Sludge Monster

Whenever Sludge Monster enters or attacks, put a slime counter on up to one other target creature.
Non-Horror creatures with slime counters on them lose all abilities and have base power and toughness 2/2.

Diabolic Tutor

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

Languish

All creatures get -4/-4 until end of turn.

Pact of Negation

Counter target spell.
At the beginning of your next upkeep, pay {3}{U}{U}. If you don't, you lose the game.

Countersquall

Counter target noncreature spell. Its controller loses 2 life.

Replicating Ring

{T}: Add one mana of any color.
At the beginning of your upkeep, put a night counter on Replicating Ring. Then if it has eight or more night counters on it, remove all of them and create eight colorless snow artifact tokens named Replicated Ring with "{T}: Add one mana of any color."

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.

Supernatural Stamina

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield tapped under its owner's control."

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Island

Morbid Opportunist

Whenever one or more other creatures die, draw a card. This ability triggers only once each turn.

Grave Betrayal

Whenever a creature you don't control dies, return it to the battlefield under your control with an additional +1/+1 counter on it at the beginning of the next end step. That creature is a black Zombie in addition to its other colors and types.

Necroskitter

Wither (This deals damage to creatures in the form of -1/-1 counters.)
Whenever a creature an opponent controls with a -1/-1 counter on it dies, you may return that card to the battlefield under your control.

Robe of Mirrors

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature has shroud. (It can't be the target of spells or abilities.)

Reliquary Tower

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

Halimar Depths

Halimar Depths enters tapped.
When Halimar Depths enters, look at the top three cards of your library, then put them back in any order.
{T}: Add {U}.

Clackbridge Troll

Trample, haste
When Clackbridge Troll enters, target opponent creates three 0/1 white Goat creature tokens.
At the beginning of combat on your turn, any opponent may sacrifice a creature of their choice. If a player does, tap Clackbridge Troll, you gain 3 life, and you draw a card.

Dark Ritual

Command Tower

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

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

Negate

Gilded Lotus

Reality Shift

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

Massacre Girl

Menace
When Massacre Girl enters, each other creature gets -1/-1 until end of turn. Whenever a creature dies this turn, each creature other than Massacre Girl gets -1/-1 until end of turn.

Dragon Throne of Tarkir

Equipped creature has defender and "{2}, {T}: Other creatures you control gain trample and get +X/+X until end of turn, where X is this creature's power."
Equip {3}

Neurok Stealthsuit

Equipped creature has shroud. (It can't be the target of spells or abilities.)
{U}{U}: Attach Neurok Stealthsuit to target creature you control.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Hunted Phantasm

Hunted Phantasm can't be blocked.
When Hunted Phantasm enters, target opponent creates five 1/1 red Goblin creature tokens.

Crumbling Ashes

At the beginning of your upkeep, destroy target creature with a -1/-1 counter on it.

Karn's Bastion

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

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.

Narset's Reversal

Copy target instant or sorcery spell, then return it to its owner's hand. You may choose new targets for the copy.

Ravenform

Exile target artifact or creature. Its controller creates a 1/1 blue Bird creature token with flying.
Foretell {U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Genesis Chamber

Whenever a nontoken creature enters, if Genesis Chamber is untapped, that creature's controller creates a 1/1 colorless Myr artifact creature token.

Fade Away

For each creature, its controller sacrifices a permanent of their choice unless they pay {1}.

Maze of Ith

{T}: Untap target attacking creature. Prevent all combat damage that would be dealt to and dealt by that creature this turn.

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

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.

Rogue's Passage

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

Village Rites

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

Mind Stone

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

Kels, Fight Fixer

Menace
Whenever you sacrifice a creature, you may pay {U/B}. If you do, draw a card. ({U/B} can be paid with either {U} or {B}.)
{1}, Sacrifice a creature: Kels, Fight Fixer gains indestructible until end of turn.

Don't Have

Thought Vessel

Forbidden Orchard

{T}: Add one mana of any color.
Whenever you tap Forbidden Orchard for mana, target opponent creates a 1/1 colorless Spirit creature token.

Hunted Horror

Trample
When Hunted Horror enters, target opponent creates two 3/3 green Centaur creature tokens with protection from black.

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}.

Swamp

Lazotep Plating

Amass Zombies 1. (Put a +1/+1 counter on an Army you control. It's also a Zombie. If you don't control an Army, create a 0/0 black Zombie Army creature token first.)
You and permanents you control gain hexproof until end of turn. (You and they can't be the targets of spells or abilities your opponents control.)

Deathgreeter

Whenever another creature dies, you may gain 1 life.

Deserted Temple

{T}: Add {C}.
{1}, {T}: Untap target land.

Vedalken Humiliator

Metalcraft — Whenever Vedalken Humiliator attacks, if you control three or more artifacts, creatures your opponents control lose all abilities and have base power and toughness 1/1 until end of turn.

Sol Ring

Glistening Sphere

Glistening Sphere enters tapped.
When Glistening Sphere enters, proliferate.
{T}: Add one mana of any color.
Corrupted — {T}: Add three mana of any one color. Activate only if an opponent has three or more poison counters.

Tainted Isle

{T}: Add {C}.
{T}: Add {U} or {B}. Activate only if you control a Swamp.

Slaughter Specialist

When Slaughter Specialist enters, each opponent creates a 1/1 white Human creature token.
Whenever a creature an opponent controls dies, put a +1/+1 counter on Slaughter Specialist.

Counterspell

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.

Blessing of Leeches

Flash
Enchant creature
At the beginning of your upkeep, you lose 1 life.
{0}: Regenerate enchanted creature.

Crawlspace

No more than two creatures can attack you each combat.

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.

Worn Powerstone

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

Black Sun's Zenith

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

Urborg, Tomb of Yawgmoth

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

Solve the Equation

Search your library for an instant or sorcery card, reveal it, put it into your hand, then shuffle.

Undying Evil

Target creature gains undying until end of turn. (When it dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Alexi's Cloak

Flash
Enchant creature
Enchanted creature has shroud. (It can't be the target of spells or abilities.)

Toxic Deluge

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

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Grave Pact

Whenever a creature you control dies, each other player sacrifices a creature of their choice.

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.")

Kormus Bell

All Swamps are 1/1 black creatures that are still lands.

Curse of the Swine

Exile X target creatures. For each creature exiled this way, its controller creates a 2/2 green Boar creature token.

Temple of Deceit

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {U} or {B}.

Ornithopter of Paradise

Resculpt

Exile target artifact or creature. Its controller creates a 4/4 blue and red Elemental creature token.

Flux Channeler

Whenever you cast a noncreature spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Delay

Counter target spell. If the spell is countered this way, exile it with three time counters on it instead of putting it into its owner's graveyard. If it doesn't have suspend, it gains suspend. (At the beginning of its owner's upkeep, they remove a time counter. When the last is removed, they may play it without paying its mana cost. If it's a creature, it has haste.)

Gisa, Glorious Resurrector

If a creature an opponent controls would die, exile it instead.
At the beginning of your upkeep, put all creature cards exiled with Gisa, Glorious Resurrector onto the battlefield under your control. They gain decayed. (A creature with decayed can't block. When it attacks, sacrifice it at end of combat.)

Mutilate

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

No Mercy

Whenever a creature deals damage to you, destroy it.

Tezzeret's Gambit

({U/P} can be paid with either {U} or 2 life.)
Draw two cards, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Spark Double

You may have Spark Double enter as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Mass Diminish

Until your next turn, creatures target player controls have base power and toughness 1/1.
Flashback {3}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Sunken Hollow

({T}: Add {U} or {B}.)
Sunken Hollow enters tapped unless you control two or more basic lands.

Akroan Horse

Defender
When Akroan Horse enters, an opponent gains control of it.
At the beginning of your upkeep, each opponent creates a 1/1 white Soldier creature token.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. Talisman of Dominance deals 1 damage to you.

Arcane Signet

Perplex

Counter target spell unless its controller discards their hand.
Transmute {1}{U}{B} ({1}{U}{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.)

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.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Blowfly Infestation

Whenever a creature dies, if it had a -1/-1 counter on it, put a -1/-1 counter on target creature.

Cabal Coffers

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

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.

Tidings

Expedition Map

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

Bubbling Muck

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

Curator's Ward

Enchant permanent
Enchanted permanent has hexproof.
When enchanted permanent leaves the battlefield, if it was historic, draw two cards. (Artifacts, legendaries, and Sagas are historic.)