Mephitic Vapors

All creatures get -1/-1 until end of turn.
Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Caustic Crawler

Landfall — Whenever a land you control enters, you may have target creature get -1/-1 until end of turn.

Illness in the Ranks

Grasping Dunes

{T}: Add {C}.
{1}, {T}, Sacrifice this land: Put a -1/-1 counter on target creature. Activate only as a sorcery.

Endbringer

Untap this creature during each other player's untap step.
{T}: This creature deals 1 damage to any target.
{C}, {T}: Target creature can't attack or block this turn.
{C}{C}, {T}: Draw a card.

Glistening Deluge

All creatures get -1/-1 until end of turn. Creatures that are green and/or white get an additional -2/-2 until end of turn.

Plague Engineer

Deathtouch
As this creature enters, choose a creature type.
Creatures of the chosen type your opponents control get -1/-1.

Caltrops

Whenever a creature attacks, this artifact deals 1 damage to it.

Night of Souls' Betrayal

Contagion Engine

When this artifact enters, put a -1/-1 counter on each creature target player controls.
{4}, {T}: Proliferate twice. (Choose any number of permanents and/or players, then give each another counter of each kind already there. Then do it again.)

Make Obsolete

Creatures your opponents control get -1/-1 until end of turn.

Orcish Bowmasters

Flash
When this creature enters and whenever an opponent draws a card except the first one they draw in each of their draw steps, this creature deals 1 damage to any target. Then amass Orcs 1.

Ascendant Evincar

Flying (This creature can't be blocked except by creatures with flying or reach.)
Other black creatures get +1/+1.
Nonblack creatures get -1/-1.

Pestilence Demon

Flying
{B}: This creature deals 1 damage to each creature and each player.

Memory of Toshiro

{T}, Pay 1 life: Add {B}. Spend this mana only to cast an instant or sorcery spell.

Life of Toshiro Umezawa

(As this Saga enters and after your draw step, add a lore counter.)
I, II — Choose one —
• Target creature gets +2/+2 until end of turn.
• Target creature gets -1/-1 until end of turn.
• You gain 2 life.
III — Exile this Saga, then return it to the battlefield transformed under your control.

Life of Toshiro Umezawa // Memory of Toshiro

Suffocating Fumes

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

Festergloom

Nonblack creatures get -1/-1 until end of turn.

Black Sun's Zenith

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

Death's-Head Buzzard

Flying
When this creature dies, all creatures get -1/-1 until end of turn.

Doomwake Giant

Constellation — Whenever this creature or another enchantment you control enters, creatures your opponents control get -1/-1 until end of turn.

Plague Mare

This creature can't be blocked by white creatures.
When this creature enters, creatures your opponents control get -1/-1 until end of turn.

Nausea

All creatures get -1/-1 until end of turn.

Cower in Fear

Kaervek, the Spiteful

Dread of Night

Dry Spell

Dry Spell deals 1 damage to each creature and each player.

Kuro, Pitlord

At the beginning of your upkeep, sacrifice Kuro unless you pay {B}{B}{B}{B}.
Pay 1 life: Target creature gets -1/-1 until end of turn.

Marsh Casualties

Kicker {3} (You may pay an additional {3} as you cast this spell.)
Creatures target player controls get -1/-1 until end of turn. If this spell was kicked, those creatures get -2/-2 until end of turn instead.

Engineered Plague

As this enchantment enters, choose a creature type.
All creatures of the chosen type get -1/-1.

Noxious Field

Enchant land
Enchanted land has "{T}: This land deals 1 damage to each creature and each player."

Erebos, Bleak-Hearted

Indestructible
As long as your devotion to black is less than five, Erebos isn't a creature.
Whenever another creature you control dies, you may pay 2 life. If you do, draw a card.
{1}{B}, Sacrifice another creature: Target creature gets -2/-1 until end of turn.

Umezawa's Jitte

Whenever equipped creature deals combat damage, put two charge counters on Umezawa's Jitte.
Remove a charge counter from Umezawa's Jitte: Choose one —
• Equipped creature gets +2/+2 until end of turn.
• Target creature gets -1/-1 until end of turn.
• You gain 2 life.
Equip {2}

Shrivel

Yawgmoth, Thran Physician

Protection from Humans
Pay 1 life, Sacrifice another creature: Put a -1/-1 counter on up to one target creature and draw a card.
{B}{B}, Discard a card: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Night Clubber

When this creature enters, creatures your opponents control get -1/-1 until end of turn.
Blitz {2}{B} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

The Black Breath

Creatures your opponents control get -1/-1 until end of turn. The Ring tempts you.

Curse of Death's Hold

Enchant player
Creatures enchanted player controls get -1/-1.

Stench of Decay

Nonartifact creatures get -1/-1 until end of turn.

Minister of Pain

Exploit (When this creature enters, you may sacrifice a creature.)
When this creature exploits a creature, creatures your opponents control get -1/-1 until end of turn.

Contagion Clasp

When this artifact enters, put a -1/-1 counter on target creature.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Liliana, the Last Hope

+1: Up to one target creature gets -2/-1 until your next turn.
−2: Mill two cards, then you may return a creature card from your graveyard to your hand.
−7: You get an emblem with "At the beginning of your end step, create X 2/2 black Zombie creature tokens, where X is two plus the number of Zombies you control."

Midnight Banshee

Wither (This deals damage to creatures in the form of -1/-1 counters.)
At the beginning of your upkeep, put a -1/-1 counter on each nonblack creature.

Neutralize the Guards

Creatures target opponent controls get -1/-1 until end of turn. Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Festering Evil

At the beginning of your upkeep, this enchantment deals 1 damage to each creature and each player.
{B}{B}, Sacrifice this enchantment: It deals 3 damage to each creature and each player.

Desert

{T}: Add {C}.
{T}: This land deals 1 damage to target attacking creature. Activate only during the end of combat step.

Phyresis Outbreak

Each opponent gets a poison counter. Then each creature your opponents control gets -1/-1 until end of turn for each poison counter its controller has.

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.

Maha, Its Feathers Night

Flying, trample
Ward—Discard a card.
Creatures your opponents control have base toughness 1.

Gruesome Realization

Choose one —
• You draw two cards and you lose 2 life.
• Creatures your opponents control get -1/-1 until end of turn.