Fellwar Stone

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

Witch's Cottage

({T}: Add {B}.)
This land enters tapped unless you control three or more other Swamps.
When this land enters untapped, you may put target creature card from your graveyard on top of your library.

Opal Palace

{T}: Add {C}.
{1}, {T}: Add one mana of any color in your commander's color identity. If you spend this mana to cast your commander, it enters with a number of additional +1/+1 counters on it equal to the number of times it's been cast from the command zone this game.

Beamsaw Prospector

When this creature dies, create a Lander token. (It's an artifact with "{2}, {T}, Sacrifice this token: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.")

Arcane Signet

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

Not Dead After All

Until end of turn, target creature you control gains "When this creature dies, return it to the battlefield tapped under its owner's control, then create a Wicked Role token attached to it." (Enchanted creature gets +1/+1. When this token is put into a graveyard, each opponent loses 1 life.)

Carrion Feeder

This creature can't block.
Sacrifice a creature: Put a +1/+1 counter on this creature.

Nasty End

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards. If the sacrificed creature was legendary, draw three cards instead.

Feed the Swarm

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

Deadly Dispute

As an additional cost to cast this spell, sacrifice an artifact or creature.
Draw two cards and create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Grim Guardian

Constellation — Whenever this creature or another enchantment you control enters, each opponent loses 1 life.

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."

Mirkwood Bats

Flying
Whenever you create or sacrifice a token, each opponent loses 1 life.

Swamp

Twisted Sewer-Witch

When this creature enters, create a 1/1 black Rat creature token with "This creature can't block." Then for each Rat you control, create a Wicked Role token attached to that Rat. (If you control another Role on it, put that one into the graveyard. Enchanted creature gets +1/+1. When this token is put into a graveyard, each opponent loses 1 life.)

Study Hall

{T}: Add {C}.
{1}, {T}: Add one mana of any color. When you spend this mana to cast your commander, scry X, where X is the number of times it's been cast from the command zone this game.

Barren Moor

This land enters tapped.
{T}: Add {B}.
Cycling {B} ({B}, Discard this card: Draw a card.)

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."

Vault of Whispers

Suffocating Fumes

Creatures your opponents control get -1/-1 until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Costly Plunder

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

Echoing Return

Return target creature card and all other cards with the same name as that card from your graveyard to your hand.

Bojuka Bog

This land enters tapped.
When this land enters, exile target player's graveyard.
{T}: Add {B}.

Grasp of Darkness

Target creature gets -4/-4 until end of turn.

Peat Bog

This land enters tapped with two depletion counters on it.
{T}, Remove a depletion counter from this land: Add {B}{B}. If there are no depletion counters on this land, sacrifice it.

Mortuary Mire

This land enters tapped.
When this land enters, you may put target creature card from your graveyard on top of your library.
{T}: Add {B}.

Gray Merchant of Asphodel

When this creature 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.)

Go for the Throat

Raise the Draugr

Choose one —
• Return target creature card from your graveyard to your hand.
• Return two target creature cards that share a creature type from your graveyard to your hand.

Darkness

Prevent all combat damage that would be dealt this turn.

Swarm Culler

Flying
Whenever this creature becomes tapped, you may sacrifice another creature or artifact. If you do, draw a card.

Corrupted Conviction

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

Reckoner's Bargain

As an additional cost to cast this spell, sacrifice an artifact or creature.
You gain life equal to the sacrificed permanent's mana value. Draw two cards.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Troll of Khazad-dûm

This creature can't be blocked except by three or more creatures.
Swampcycling {1} ({1}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)

Dimir House Guard

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Sacrifice a creature: Regenerate this creature.
Transmute {1}{B}{B} ({1}{B}{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.)

Ashnod's Altar

Sign in Blood

Target player draws two cards and loses 2 life.

Bubbling Muck

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

Undying Malice

Cabal Ritual

Add {B}{B}{B}.
Threshold — Add {B}{B}{B}{B}{B} instead if seven or more cards are in your graveyard.

Culling the Weak

As an additional cost to cast this spell, sacrifice a creature.
Add {B}{B}{B}{B}.

Warehouse Tabby

Whenever an enchantment you control is put into a graveyard from the battlefield, create a 1/1 black Rat creature token with "This token can't block."
{1}{B}: This creature gains deathtouch until end of turn.

Decode Transmissions

You draw two cards and lose 2 life.
Void — If a nonland permanent left the battlefield this turn or a spell was warped this turn, instead you draw two cards and each opponent loses 2 life.

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Wicked Visitor

Whenever an enchantment you control is put into a graveyard from the battlefield, each opponent loses 1 life.

Victim of Night

Destroy target non-Vampire, non-Werewolf, non-Zombie creature.

Return from Extinction

Village Rites

Dark Ritual

Relentless Rats

This creature gets +1/+1 for each other creature on the battlefield named Relentless Rats.
A deck can have any number of cards named Relentless Rats.