minus

Whenever you put one or more counters on a permanent or player, All Will Be One deals that much damage to target opponent, creature an opponent controls, or planeswalker an opponent controls.

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

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

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

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

Flying

Carnifex Demon enters the battlefield with two -1/-1 counters on it.

{B}, Remove a -1/-1 counter from Carnifex Demon: Put a -1/-1 counter on each other creature.

When Channeler Initiate enters the battlefield, put three -1/-1 counters on target creature you control.

{T}, Remove a -1/-1 counter from Channeler Initiate: Add one mana of any color.

Destroy any number of target creatures. For each creature destroyed this way, its controller creates a 4/4 red Dragon creature token with flying.

Whenever Dusk Urchins attacks or blocks, put a -1/-1 counter on it.

When Dusk Urchins dies, draw a card for each -1/-1 counter on it.

Players can't gain life.

Damage can't be prevented.

All damage is dealt as though its source had wither. (A source with wither deals damage to creatures in the form of -1/-1 counters.)

({T}: Add {G}.)

When Generous Patron enters the battlefield, support 2. (Put a +1/+1 counter on each of up to two other target creatures.)

Whenever you put one or more counters on a creature you don't control, draw a card.

Golgari Guildgate enters the battlefield tapped.

{T}: Add {B} or {G}.

Gruul Guildgate enters the battlefield tapped.

{T}: Add {R} or {G}.

Whenever Hapatra, Vizier of Poisons deals combat damage to a player, you may put a -1/-1 counter on target creature.

Whenever you put one or more -1/-1 counters on a creature, create a 1/1 green Snake creature token with deathtouch.

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.

({T}: Add {R}.)

Devour 2 (As this enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with twice that many +1/+1 counters on it.)

At the beginning of your upkeep, create a 1/1 green Saproling creature token for each +1/+1 counter on Mycoloth.

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.

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

Reach

Whenever Obelisk Spider deals combat damage to a creature, put a -1/-1 counter on that creature.

Whenever you put one or more -1/-1 counters on a creature, each opponent loses 1 life and you gain 1 life.

Rakdos Guildgate enters the battlefield tapped.

{T}: Add {B} or {R}.

Savage Lands enters the battlefield tapped.

{T}: Add {B}, {R}, or {G}.

As an additional cost to cast this spell, put a -1/-1 counter on a creature you control.

Draw two cards.

When Soul Snuffers enters the battlefield, put a -1/-1 counter on each creature.

({T}: Add {B}.)

Whenever a creature with a -1/-1 counter on it dies, draw a card.

{1}{B}{R}: Put a -1/-1 counter on another target creature.

When The Scorpion God dies, return it to its owner's hand at the beginning of the next end step.

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.)