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.)

Staff of Compleation

{T}, Pay 1 life: Destroy target permanent you own.
{T}, Pay 2 life: Add one mana of any color.
{T}, Pay 3 life: Proliferate.
{T}, Pay 4 life: Draw a card.
{5}: Untap Staff of Compleation.

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Storm of Forms

When you cast this spell, copy it for each kind of counter among permanents you control. You may choose new targets for the copies.
Return target nonland permanent to its owner's hand.

As Foretold

At the beginning of your upkeep, put a time counter on As Foretold.
Once each turn, you may pay {0} rather than pay the mana cost for a spell you cast with mana value X or less, where X is the number of time counters on As Foretold.

Sphinx of Magosi

Flying
{2}{U}: Draw a card, then put a +1/+1 counter on Sphinx of Magosi.

Spark Double

You may have Spark Double enter as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Curse of the Swine

Exile X target creatures. For each creature exiled this way, its controller creates a 2/2 green Boar creature token.

Deepglow Skate

When Deepglow Skate enters, double the number of each kind of counter on any number of target permanents.

Aven Courier

Flying
Whenever Aven Courier attacks, choose a counter on a permanent you control. Put a counter of that kind on target permanent you control if it doesn't have a counter of that kind on it.

Tamiyo, the Moon Sage

+1: Tap target permanent. It doesn't untap during its controller's next untap step.
−2: Draw a card for each tapped creature target player controls.
−8: You get an emblem with "You have no maximum hand size" and "Whenever a card is put into your graveyard from anywhere, you may return it to your hand."

Karn's Bastion

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Teferi, Temporal Pilgrim

Whenever you draw a card, put a loyalty counter on Teferi, Temporal Pilgrim.
0: Draw a card.
−2: Create a 2/2 blue Spirit creature token with vigilance and "Whenever you draw a card, put a +1/+1 counter on this creature."
−12: Target opponent chooses a permanent they control and returns it to its owner's hand. Then they shuffle each nonland permanent they control into its owner's library.

Fuel for the Cause

Counter target spell, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Thought Sponge

Flash
Thought Sponge enters with a number of +1/+1 counters on it equal to the greatest number of cards an opponent has drawn this turn.
When Thought Sponge dies, draw cards equal to its power.

Viral Drake

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{3}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Suspend

Exile target creature and put two time counters on it. If it doesn't have suspend, it gains suspend. (At the beginning of its owner's upkeep, they remove a time counter. When the last is removed, they may play it without paying its mana cost. If it's a creature, it has haste.)

Chasm Skulker

Whenever you draw a card, put a +1/+1 counter on Chasm Skulker.
When Chasm Skulker dies, create X 1/1 blue Squid creature tokens with islandwalk, where X is the number of +1/+1 counters on Chasm Skulker. (They can't be blocked as long as defending player controls an Island.)

Gavel of the Righteous

At the beginning of combat on your turn, put a charge counter on Gavel of the Righteous.
Equipped creature gets +1/+1 for each counter on Gavel of the Righteous.
As long as Gavel of the Righteous has four or more counters on it, equipped creature has double strike.
Equip—Pay {3} or remove a counter from Gavel of the Righteous.

Narset, Parter of Veils

Each opponent can't draw more than one card each turn.
−2: Look at the top four cards of your library. You may reveal a noncreature, nonland card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Darksteel Reactor

Indestructible (Effects that say "destroy" don't destroy this artifact.)
At the beginning of your upkeep, you may put a charge counter on Darksteel Reactor.
When Darksteel Reactor has twenty or more charge counters on it, you win the game.

Cosi's Trickster

Whenever an opponent shuffles their library, you may put a +1/+1 counter on Cosi's Trickster.

Tezzeret, Artifice Master

+1: Create a 1/1 colorless Thopter artifact creature token with flying.
0: Draw a card. If you control three or more artifacts, draw two cards instead.
−9: You get an emblem with "At the beginning of your end step, search your library for a permanent card, put it onto the battlefield, then shuffle."

Teferi's Talent

Enchant planeswalker
Enchanted planeswalker has "[−12]: You get an emblem with 'You may activate loyalty abilities of planeswalkers you control on any player's turn any time you could cast an instant.'"
Whenever you draw a card, put a loyalty counter on enchanted planeswalker.

Forge of Heroes

{T}: Add {C}.
{T}: Choose target commander that entered this turn. Put a +1/+1 counter on it if it's a creature and a loyalty counter on it if it's a planeswalker.

Hangarback Walker

Hangarback Walker enters with X +1/+1 counters on it.
When Hangarback Walker dies, create a 1/1 colorless Thopter artifact creature token with flying for each +1/+1 counter on Hangarback Walker.
{1}, {T}: Put a +1/+1 counter on Hangarback Walker.

Core Prowler

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
When Core Prowler dies, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Island

Strixhaven Stadium

{T}: Add {C}. Put a point counter on Strixhaven Stadium.
Whenever a creature deals combat damage to you, remove a point counter from Strixhaven Stadium.
Whenever a creature you control deals combat damage to an opponent, put a point counter on Strixhaven Stadium. Then if it has ten or more point counters on it, remove them all and that player loses the game.

Everflowing Chalice

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
Everflowing Chalice enters with a charge counter on it for each time it was kicked.
{T}: Add {C} for each charge counter on Everflowing Chalice.

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.)

Aetherize

Return all attacking creatures to their owner's hand.

Magistrate's Scepter

{4}, {T}: Put a charge counter on Magistrate's Scepter.
{T}, Remove three charge counters from Magistrate's Scepter: Take an extra turn after this one.

Gitaxian Anatomist

When Gitaxian Anatomist enters, you may tap it. If you do, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Thrummingbird

Flying
Whenever Thrummingbird deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Wingspan Mentor

When Wingspan Mentor enters, put a flying counter on target non-Human creature you control.
{2}{U}, {T}: Put a +1/+1 counter on each creature you control with flying.

Academy Elite

Academy Elite enters with X +1/+1 counters on it, where X is the number of instant and sorcery cards in all graveyards.
{2}{U}, Remove a +1/+1 counter from Academy Elite: Draw a card, then discard a card.

Myojin of Cryptic Dreams

Myojin of Cryptic Dreams enters with an indestructible counter on it if you cast it from your hand.
Remove an indestructible counter from Myojin of Cryptic Dreams: Copy target permanent spell you control three times. (The copies become tokens.)

Steady Progress

Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Draw a card.

Saiba Cryptomancer

Flash
Backup 1 (When this creature enters, put a +1/+1 counter on target creature. If that's another creature, it gains the following ability until end of turn.)
Hexproof

Kiora's Dambreaker

When Kiora's Dambreaker enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Essence Capture

Counter target creature spell. Put a +1/+1 counter on up to one target creature you control.

Jace, Unraveler of Secrets

+1: Scry 1, then draw a card.
−2: Return target creature to its owner's hand.
−8: You get an emblem with "Whenever an opponent casts their first spell each turn, counter that spell."

Chrome Host Seedshark

Flying
Whenever you cast a noncreature spell, incubate X, where X is that spell's mana value. (Create an Incubator token with X +1/+1 counters on it and "{2}: Transform this artifact." It transforms into a 0/0 Phyrexian artifact creature.)

Skyship Plunderer

Flying
Whenever Skyship Plunderer deals combat damage to a player, for each kind of counter on target permanent or player, give that permanent or player another counter of that kind.

Serum Sovereign

Flying
Whenever you cast a noncreature spell, put an oil counter on Serum Sovereign.
{U}, Remove an oil counter from Serum Sovereign: Draw a card, then scry 2.

Orochi Hatchery

Orochi Hatchery enters with X charge counters on it.
{5}, {T}: Create a 1/1 green Snake creature token for each charge counter on Orochi Hatchery.

Vivisurgeon's Insight

Draw three cards. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Nesting Grounds

{T}: Add {C}.
{1}, {T}: Move a counter from target permanent you control onto another target permanent. Activate only as a sorcery.

Sinister Concierge

When Sinister Concierge dies, you may exile it and put three time counters on it. If you do, exile up to one target creature and put three time counters on it. Each card exiled this way that doesn't have suspend gains suspend. (For each card with suspend, its owner removes a time counter from it at the beginning of their upkeep. When the last is removed, they may cast it without paying its mana cost. Those creature spells have haste.)

Parallax Tide

Fading 5 (This enchantment enters with five fade counters on it. At the beginning of your upkeep, remove a fade counter from it. If you can't, sacrifice it.)
Remove a fade counter from Parallax Tide: Exile target land.
When Parallax Tide leaves the battlefield, each player returns to the battlefield all cards they own exiled with Parallax Tide.

Flux Channeler

Whenever you cast a noncreature spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Experimental Augury

Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Aether Figment

Kicker {3} (You may pay an additional {3} as you cast this spell.)
Aether Figment can't be blocked.
If Aether Figment was kicked, it enters with two +1/+1 counters on it.

Contentious Plan

Mesmerizing Dose

Enchant creature
When Mesmerizing Dose enters, tap enchanted creature, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Enchanted creature doesn't untap during its controller's untap step.

Ledger Shredder

Flying
Whenever a player casts their second spell each turn, Ledger Shredder connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Remote Isle

Remote Isle enters tapped.
{T}: Add {U}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Inexorable Tide

Whenever you cast a spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Reject Imperfection

Counter target spell. If that spell's mana value was 3 or less, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Replicating Ring

{T}: Add one mana of any color.
At the beginning of your upkeep, put a night counter on Replicating Ring. Then if it has eight or more night counters on it, remove all of them and create eight colorless snow artifact tokens named Replicated Ring with "{T}: Add one mana of any color."

Field of Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice Field of Ruin: Destroy target nonbasic land an opponent controls. Each player searches their library for a basic land card, puts it onto the battlefield, then shuffles.

Archmage's Charm

Choose one —
• Counter target spell.
• Target player draws two cards.
• Gain control of target nonland permanent with mana value 1 or less.

Relearn

Return target instant or sorcery card from your graveyard to your hand.

Desert of the Mindful

Desert of the Mindful enters tapped.
{T}: Add {U}.
Cycling {1}{U} ({1}{U}, Discard this card: Draw a card.)

Serum Snare

Return target nonland permanent to its owner's hand. If that permanent had mana value 3 or less, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Jwari Ruins

Jwari Disruption

Counter target spell unless its controller pays {1}.

Jwari Disruption // Jwari Ruins

Ichormoon Gauntlet

Planeswalkers you control have "[0]: Proliferate" and "[−12]: Take an extra turn after this one."
Whenever you cast a noncreature spell, choose a counter on target permanent. Put an additional counter of that kind on that permanent.

Teferi, Master of Time

You may activate loyalty abilities of Teferi, Master of Time on any player's turn any time you could cast an instant.
+1: Draw a card, then discard a card.
−3: Target creature you don't control phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)
−10: Take two extra turns after this one.

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.

Tezzeret's Gambit

({U/P} can be paid with either {U} or 2 life.)
Draw two cards, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Spectral Adversary

Flash
Flying
When Spectral Adversary enters, you may pay {1}{U} any number of times. When you pay this cost one or more times, put that many +1/+1 counters on Spectral Adversary, then up to that many other target artifacts, creatures, and/or enchantments phase out.

Astral Cornucopia

Astral Cornucopia enters with X charge counters on it.
{T}: Choose a color. Add one mana of that color for each charge counter on Astral Cornucopia.

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.)