Have

Obelisk Spider

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.

Glistening Oil

Enchant creature
Enchanted creature has infect.
At the beginning of your upkeep, put a -1/-1 counter on enchanted creature.
When Glistening Oil is put into a graveyard from the battlefield, return Glistening Oil to its owner's hand.

The Ozolith

Whenever a creature you control leaves the battlefield, if it had counters on it, put those counters on The Ozolith.
At the beginning of combat on your turn, if The Ozolith has counters on it, you may move all counters from The Ozolith onto target creature.

Lockjaw Snapper

Wither (This deals damage to creatures in the form of -1/-1 counters.)
When Lockjaw Snapper dies, put a -1/-1 counter on each creature with a -1/-1 counter on it.

Compy Swarm

At the beginning of your end step, if a creature died this turn, create a tapped token that's a copy of Compy Swarm.

Biting Tether

Enchant creature
You control enchanted creature.
At the beginning of your upkeep, put a -1/-1 counter on enchanted creature.

Lethal Sting

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

Canker Abomination

As Canker Abomination enters, choose an opponent. Canker Abomination enters with a -1/-1 counter on it for each creature that player controls.

Mirkwood Bats

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

Forest

Volrath, the Shapestealer

At the beginning of combat on your turn, put a -1/-1 counter on up to one target creature.
{1}: Until your next turn, Volrath, the Shapestealer becomes a copy of target creature with a counter on it, except it's 7/5 and it has this ability.

Carnifex Demon

Flying
Carnifex Demon enters 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.

Swamp

Return to Nature

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Exile target card from a graveyard.

Contagion Clasp

When Contagion Clasp 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.)

Contagion Engine

When Contagion Engine 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.)

Thriving Isle

Thriving Isle enters tapped. As it enters, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

Naturalize

Nadier's Nightblade

Whenever a token you control leaves the battlefield, each opponent loses 1 life and you gain 1 life.

Corrosive Mentor

Black creatures you control have wither. (They deal damage to creatures in the form of -1/-1 counters.)

Nest of Scarabs

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

Dig Up

Cleave {1}{B}{B}{G} (You may cast this spell for its cleave cost. If you do, remove the words in square brackets.)
Search your library for a [basic land] card, [reveal it,] put it into your hand, then shuffle.

Blight Mamba

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

Serrated Biskelion

{T}: Put a -1/-1 counter on Serrated Biskelion and a -1/-1 counter on target creature.

Tekuthal, Inquiry Dominus

Flying
If you would proliferate, proliferate twice instead.
{1}{U/P}{U/P}, Remove three counters from among other artifacts, creatures, and planeswalkers you control: Put an indestructible counter on Tekuthal, Inquiry Dominus. ({U/P} can be paid with either {U} or 2 life.)

Winding Constrictor

If one or more counters would be put on an artifact or creature you control, that many plus one of each of those kinds of counters are put on that permanent instead.
If you would get one or more counters, you get that many plus one of each of those kinds of counters instead.

Dusk Urchins

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.

Juvenile Gloomwidow

Reach (This creature can block creatures with flying.)
Wither (This deals damage to creatures in the form of -1/-1 counters.)

Getting

Pir, Imaginative Rascal

Partner with Toothy, Imaginary Friend (When this creature enters, target player may put Toothy into their hand from their library, then shuffle.)
If one or more counters would be put on a permanent your team controls, that many plus one of each of those kinds of counters are put on that permanent instead.

Incremental Blight

Put a -1/-1 counter on target creature, two -1/-1 counters on another target creature, and three -1/-1 counters on a third target creature.

Phyrexian Hydra

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
If damage would be dealt to Phyrexian Hydra, prevent that damage. Put a -1/-1 counter on Phyrexian Hydra for each 1 damage prevented this way.

Doubling Season

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

Hapatra, Vizier of Poisons

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.

Leech Bonder

Leech Bonder enters with two -1/-1 counters on it.
{U}, {Q}: Move a counter from target creature onto a second target creature. ({Q} is the untap symbol.)

Diabolic Intent

As an additional cost to cast this spell, sacrifice a creature.
Search your library for a card, put that card into your hand, then shuffle.

Thriving Moor

Thriving Moor enters tapped. As it enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Necroskitter

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.

Reflecting Pool

{T}: Add one mana of any type that a land you control could produce.

Giant Oyster

You may choose not to untap Giant Oyster during your untap step.
{T}: For as long as Giant Oyster remains tapped, target tapped creature doesn't untap during its controller's untap step, and at the beginning of each of your draw steps, put a -1/-1 counter on that creature. When Giant Oyster leaves the battlefield or becomes untapped, remove all -1/-1 counters from the creature.

Skithiryx, the Blight Dragon

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{B}: Skithiryx, the Blight Dragon gains haste until end of turn.
{B}{B}: Regenerate Skithiryx.

Persist

Return target nonlegendary creature card from your graveyard to the battlefield with a -1/-1 counter on it.

Command Tower

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

Skeleton Ship

When you control no Islands, sacrifice Skeleton Ship.
{T}: Put a -1/-1 counter on target creature.

Simic Signet

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.

Arcane Signet

Torture

Enchant creature
{1}{B}: Put a -1/-1 counter on enchanted creature.

Tangle Angler

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{G}: Target creature blocks Tangle Angler this turn if able.

Thriving Grove

Thriving Grove enters tapped. As it enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X 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.

Blowfly Infestation

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

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Cinderbones

Wither (This deals damage to creatures in the form of -1/-1 counters.)
{1}{B}: Regenerate Cinderbones.

Island

Triumph of the Hordes

Until end of turn, creatures you control get +1/+1 and gain trample and infect. (Creatures with infect deal damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Sol Ring

Massacre Girl, Known Killer

Menace
Creatures you control have wither. (They deal damage to creatures in the form of -1/-1 counters.)
Whenever a creature an opponent controls dies, if its toughness was less than 1, draw a card.

Scarscale Ritual

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

Flourishing Defenses

Whenever a -1/-1 counter is put on a creature, you may create a 1/1 green Elf Warrior creature token.

Blood Artist

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

Trinket Mage

When Trinket Mage enters, you may search your library for an artifact card with mana value 1 or less, reveal that card, put it into your hand, then shuffle.

Muldrotha, the Gravetide

During each of your turns, you may play a land and cast a permanent spell of each permanent type from your graveyard. (If a card has multiple permanent types, choose one as you play it.)

Attempted Murder

Choose target creature. Roll X six-sided dice. For each even result, put two -1/-1 counters on that creature. For each odd result, create a 1/2 blue Bird creature token with flying named Storm Crow.

Crumbling Ashes

At the beginning of your upkeep, destroy target creature with a -1/-1 counter on it.

Spitting Dilophosaurus

Whenever Spitting Dilophosaurus enters or attacks, put a -1/-1 counter on up to one target creature.
Creatures your opponents control with -1/-1 counters on them can't block.

Dimir Signet

Beseech the Mirror

Bargain (You may sacrifice an artifact, enchantment, or token as you cast this spell.)
Search your library for a card, exile it face down, then shuffle. If this spell was bargained, you may cast the exiled card without paying its mana cost if that spell's mana value is 4 or less. Put the exiled card into your hand if it wasn't cast this way.

Channeler Initiate

When Channeler Initiate enters, 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.

Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Urza's Saga gains "{T}: Add {C}."
II — Urza's Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This creature gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

Zagoth Triome

({T}: Add {B}, {G}, or {U}.)
Zagoth Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Necropede

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
When Necropede dies, you may put a -1/-1 counter on target creature.

Sinking Feeling

Enchant creature
Enchanted creature doesn't untap during its controller's untap step.
Enchanted creature has "{1}, Put a -1/-1 counter on this creature: Untap this creature."