Swamp

Festering Mummy

When Festering Mummy dies, you may put a -1/-1 counter on target creature.

Blessing of Belzenlok

Target creature gets +2/+1 until end of turn. If it's legendary, it also gains lifelink until end of turn.

Consume Spirit

Spend only black mana on X.
Consume Spirit deals X damage to any target and you gain X life.

Blood Glutton

Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Phyresis

Enchant creature
Enchanted creature has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Death Watch

Enchant creature
When enchanted creature dies, its controller loses life equal to its power and you gain life equal to its toughness.

Cannibalize

Choose two target creatures controlled by the same player. Exile one of those creatures and put two +1/+1 counters on the other.

Sorceress Queen

{T}: Target creature other than Sorceress Queen has base power and toughness 0/2 until end of turn.

Rathi Trapper

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters the battlefield, 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.)

Tower of Coireall

{T}: Target creature can't be blocked by Walls this turn.

Dauthi Trapper

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

Gravebind

Target creature can't be regenerated this turn.
Draw a card at the beginning of the next turn's upkeep.

Dreamspoiler Witches

Flying
Whenever you cast a spell during an opponent's turn, you may have target creature get -1/-1 until end of turn.

Afflict

Target creature gets -1/-1 until end of turn.
Draw a card.

Scale of Chiss-Goria

Flash
Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
{T}: Target creature gets +0/+1 until end of turn.

Dirge of Dread

All creatures gain fear until end of turn. (They can't be blocked except by artifact creatures and/or black creatures.)
Cycling {1}{B} ({1}{B}, Discard this card: Draw a card.)
When you cycle Dirge of Dread, you may have target creature gain fear until end of turn.

Fourth Bridge Prowler

When Fourth Bridge Prowler enters the battlefield, you may have target creature get -1/-1 until end of turn.

Alley Grifters

Whenever Alley Grifters becomes blocked, defending player discards a card.

Ghosts of the Damned

{T}: Target creature gets -1/-0 until end of turn.

Dauthi Jackal

Shadow (This creature can block or be blocked by only creatures with shadow.)
{B}{B}, Sacrifice Dauthi Jackal: Destroy target blocking creature.

Armor Thrull

{T}, Sacrifice Armor Thrull: Put a +1/+2 counter on target creature.

Fungal Infection

Target creature gets -1/-1 until end of turn. Create a 1/1 green Saproling creature token.

Frozen Shade

{B}: Frozen Shade gets +1/+1 until end of turn.

Arcane Signet

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

Squee's Toy

{T}: Prevent the next 1 damage that would be dealt to target creature this turn.

Helm of Chatzuk

{1}, {T}: Target creature gains banding until end of turn. (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding a player controls are blocking or being blocked by a creature, that player divides that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Defile

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

Bog Smugglers

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Disfigure

Target creature gets -2/-2 until end of turn.

Horobi, Death's Wail

Flying
Whenever a creature becomes the target of a spell or ability, destroy that creature.

Shadow Alley Denizen

Whenever another black creature enters the battlefield under your control, target creature gains intimidate until end of turn. (It can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Dauthi Mercenary

Shadow (This creature can block or be blocked by only creatures with shadow.)
{1}{B}: Dauthi Mercenary gets +1/+0 until end of turn.

Disciple of Tevesh Szat

{T}: Target creature gets -1/-1 until end of turn.
{4}{B}{B}, {T}, Sacrifice Disciple of Tevesh Szat: Target creature gets -6/-6 until end of turn.

Mind Stone

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

Lose Hope

Target creature gets -1/-1 until end of turn. Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

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.

Dead Revels

Spectacle {1}{B} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Return up to two target creature cards from your graveyard to your hand.

Disturbing Plot

Return target creature card from a graveyard to its owner's hand.
Conspire (As you cast this spell, you may tap two untapped creatures you control that share a color with it. When you do, copy it and you may choose a new target for the copy.)

Death Denied

Return X target creature cards from your graveyard to your hand.

Contagious Nim

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Toxic Nim

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{B}: Regenerate Toxic Nim.

Bladebrand

Target creature gains deathtouch until end of turn.
Draw a card.

Ancestral Vengeance

Enchant creature
When Ancestral Vengeance enters the battlefield, put a +1/+1 counter on target creature you control.
Enchanted creature gets -1/-1.

Agent of Shauku

{1}{B}, Sacrifice a land: Target creature gets +2/+0 until end of turn.

Forever Young

Put any number of target creature cards from your graveyard on top of your library.
Draw a card.

Aphotic Wisps

Target creature becomes black and gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)
Draw a card.

Dungeon Shade

Flying
{B}: Dungeon Shade gets +1/+1 until end of turn.

Blister Beetle

When Blister Beetle enters the battlefield, target creature gets -1/-1 until end of turn.

Xenic Poltergeist

{T}: Until your next upkeep, target noncreature artifact becomes an artifact creature with power and toughness each equal to its mana value.

Dauthi Horror

Shadow (This creature can block or be blocked by only creatures with shadow.)
Dauthi Horror can't be blocked by white creatures.

Dauthi Marauder

Shadow (This creature can block or be blocked by only creatures with shadow.)

Footbottom Feast

Flensermite

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Nighthaze

Target creature gains swampwalk until end of turn. (It can't be blocked as long as defending player controls a Swamp.)
Draw 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.)

Dauthi Slayer

Shadow (This creature can block or be blocked by only creatures with shadow.)
Dauthi Slayer attacks each combat if able.

Drifting Shade

Flying
{B}: Drifting Shade gets +1/+1 until end of turn.

Blackcleave Goblin

Haste
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Dark Ritual

Tooth of Chiss-Goria

Flash
Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
{T}: Target creature gets +1/+0 until end of turn.

Dirtwater Wraith

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
{B}: Dirtwater Wraith gets +1/+0 until end of turn.

Death's Duet

Return two target creature cards from your graveyard to your hand.

Eye Gouge

Target creature gets -1/-1 until end of turn. If it's a Cyclops, destroy it.

Deathspore Thallid

At the beginning of your upkeep, put a spore counter on Deathspore Thallid.
Remove three spore counters from Deathspore Thallid: Create a 1/1 green Saproling creature token.
Sacrifice a Saproling: Target creature gets -1/-1 until end of turn.