Defile

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

Death Wind

Target creature gets -X/-X until end of turn.

Falkenrath Noble

Flying
Whenever Falkenrath Noble or another creature dies, target player loses 1 life and you gain 1 life.

Unlikely Aid

Target creature gets +2/+0 and gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Accorder's Shield

Equipped creature gets +0/+3 and has vigilance. (Attacking doesn't cause it to tap.)
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

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.)

Assassinate

Ulamog's Crusher

Annihilator 2 (Whenever this creature attacks, defending player sacrifices two permanents of their choice.)
Ulamog's Crusher attacks each combat if able.

Tendrils of Corruption

Tendrils of Corruption deals X damage to target creature and you gain X life, where X is the number of Swamps you control.

Swamp

Eldrazi Devastator

Accursed Spirit

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Herald of Hadar

Circle of Death — {5}{B}: Roll a d20.
1—9 | Each opponent loses 2 life.
10—19 | Each opponent loses 2 life and you gain 2 life.
20 | Each opponent loses 2 life and you gain 2 life. Create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Doomed Dissenter

When Doomed Dissenter dies, create a 2/2 black Zombie creature token.

Gloom Sower

Whenever Gloom Sower becomes blocked by a creature, that creature's controller loses 2 life and you gain 2 life.

Call to the Netherworld

Return target black creature card from your graveyard to your hand.
Madness {0} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Haunted Cloak

Equipped creature has vigilance, trample, and haste.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Dark Ritual

Writhing Necromass

This spell costs {1} less to cast for each creature card in your graveyard.
Deathtouch

Fleetfeather Sandals

Equipped creature has flying and haste.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Commander's Sphere

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

Locthwain Paladin

Menace (This creature can't be blocked except by two or more creatures.)
Adamant — If at least three black mana was spent to cast this spell, Locthwain Paladin enters with a +1/+1 counter on it.

Dross Golem

Affinity for Swamps (This spell costs {1} less to cast for each Swamp you control.)
Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

Sign in Blood

Target player draws two cards and loses 2 life.

Howl from Beyond

Target creature gets +X/+0 until end of turn.

Endless Scream

Enchant creature
Endless Scream enters with X scream counters on it.
Enchanted creature gets +1/+0 for each scream counter on Endless Scream.

Arcane Signet

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

Inkrise Infiltrator

Flying
{3}{B}: Inkrise Infiltrator gets +2/+2 until end of turn.

Alley Strangler

Corrupt

Corrupt deals damage to any target equal to the number of Swamps you control. You gain life equal to the damage dealt this way.

Depraved Harvester

Desperate Farmer

Lifelink
When another creature you control dies, transform Desperate Farmer.

Desperate Farmer // Depraved Harvester

Asphyxiate

Canal Monitor

Squelching Leeches

Squelching Leeches's power and toughness are each equal to the number of Swamps you control.

Explorer's Scope

Whenever equipped creature attacks, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Cremate

Exile target card from a graveyard.
Draw a card.

Sludge Crawler

Devoid (This card has no color.)
Ingest (Whenever this creature deals combat damage to a player, that player exiles the top card of their library.)
{2}: Sludge Crawler gets +1/+1 until end of turn.

Ruin Processor

When you cast this spell, you may put a card an opponent owns from exile into that player's graveyard. If you do, you gain 5 life.

Murder

Cloak of the Bat

Blight-Breath Catoblepas

When Blight-Breath Catoblepas enters, target creature an opponent controls gets -X/-X until end of turn, where X is your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Crypt Rats

{X}: Crypt Rats deals X damage to each creature and each player. Spend only black mana on X.

Undying Malice

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."

Quag Sickness

Enchant creature
Enchanted creature gets -1/-1 for each Swamp you control.

Armillary Sphere

{2}, {T}, Sacrifice Armillary Sphere: Search your library for up to two basic land cards, reveal them, put them into your hand, then shuffle.

Baleful Beholder

When Baleful Beholder enters, choose one —
• Antimagic Cone — Each opponent sacrifices an enchantment of their choice.
• Fear Ray — Creatures you control gain menace until end of turn. (A creature with menace can't be blocked except by two or more creatures.)

Tizerus Charger

Escape—{4}{B}, Exile five other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)
Tizerus Charger escapes with your choice of a +1/+1 counter or a flying counter on it.

Disembowel

Destroy target creature with mana value X.

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."

Gurmag Angler

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)

Marshmist Titan

This spell costs {X} less to cast, where X is your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Amorphous Axe

Equipped creature gets +3/+0 and is every creature type.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Prowling Pangolin

When Prowling Pangolin enters, any player may sacrifice two creatures of their choice. If a player does, sacrifice Prowling Pangolin.

Hound of the Farbogs

Delirium — Hound of the Farbogs has menace as long as there are four or more card types among cards in your graveyard. (A creature with menace can't be blocked except by two or more creatures.)

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Shamble Back

Exile target creature card from a graveyard. Create a 2/2 black Zombie creature token. You gain 2 life.

Morkrut Behemoth

As an additional cost to cast this spell, sacrifice a creature or pay {1}{B}.
Menace (This creature can't be blocked except by two or more creatures.)

Tragic Slip

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.

Doom Blade

Gruesome Deformity

Enchant creature
Enchanted creature has intimidate. (It can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Yuan-Ti Fang-Blade

Deathtouch
Whenever Yuan-Ti Fang-Blade deals combat damage to a player, venture into the dungeon. (Enter the first room or advance to the next room.)

Mire's Toll

Target player reveals a number of cards from their hand equal to the number of Swamps you control. You choose one of them. That player discards that card.

Aether Poisoner

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When Aether Poisoner enters, you get {E}{E} (two energy counters).
Whenever Aether Poisoner attacks, you may pay {E}{E}. If you do, create a 1/1 colorless Servo artifact creature token.

Expedition Map

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

Alchemist's Vial

When Alchemist's Vial enters, draw a card.
{1}, {T}, Sacrifice Alchemist's Vial: Target creature can't attack or block this turn.

Liliana's Shade

When Liliana's Shade enters, you may search your library for a Swamp card, reveal it, put it into your hand, then shuffle.
{B}: Liliana's Shade gets +1/+1 until end of turn.