Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Noxious Revival

({G/P} can be paid with either {G} or 2 life.)
Put target card from a graveyard on top of its owner's library.

Counterspell

Toothy, Imaginary Friend

Partner with Pir, Imaginative Rascal (When this creature enters, target player may put Pir into their hand from their library, then shuffle.)
Whenever you draw a card, put a +1/+1 counter on Toothy, Imaginary Friend.
When Toothy leaves the battlefield, draw a card for each +1/+1 counter on it.

Rejuvenating Springs

Rejuvenating Springs enters tapped unless you have two or more opponents.
{T}: Add {G} or {U}.

Mystical Tutor

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

Hardened Scales

If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Worldly Tutor

Search your library for a creature card, reveal it, then shuffle and put the card on top.

Laboratory Maniac

If you would draw a card while your library has no cards in it, you win the game instead.

Forest

Defiler of Vigor

Trample
As an additional cost to cast green permanent spells, you may pay 2 life. Those spells cost {G} less to cast if you paid life this way. This effect reduces only the amount of green mana you pay.
Whenever you cast a green permanent spell, put a +1/+1 counter on each creature you control.

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

Inspiring Call

Draw a card for each creature you control with a +1/+1 counter on it. Those creatures gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

Gyre Sage

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
{T}: Add {G} for each +1/+1 counter on Gyre Sage.

Psychosis Crawler

Psychosis Crawler's power and toughness are each equal to the number of cards in your hand.
Whenever you draw a card, each opponent loses 1 life.

Simic Ascendancy

{1}{G}{U}: Put a +1/+1 counter on target creature you control.
Whenever one or more +1/+1 counters are put on a creature you control, put that many growth counters on Simic Ascendancy.
At the beginning of your upkeep, if Simic Ascendancy has twenty or more growth counters on it, you win the game.

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Scavenging Ooze

{G}: Exile target card from a graveyard. If it was a creature card, put a +1/+1 counter on this creature and you gain 1 life.

Sol Ring

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.
{T}: Add {C}{C}.

Deepglow Skate

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

Hinterland Harbor

Hinterland Harbor enters tapped unless you control a Forest or an Island.
{T}: Add {G} or {U}.

Evolution Sage

Landfall — Whenever a land you control enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Tropical Island

Boseiju, Who Shelters All

Boseiju, Who Shelters All enters tapped.
{T}, Pay 2 life: Add {C}. If that mana is spent on an instant or sorcery spell, that spell can't be countered.

Forgotten Ancient

Whenever a player casts a spell, you may put a +1/+1 counter on Forgotten Ancient.
At the beginning of your upkeep, you may move any number of +1/+1 counters from Forgotten Ancient onto other creatures.

Pir's Whim

For each player, choose friend or foe. Each friend searches their library for a land card, puts it onto the battlefield tapped, then shuffles. Each foe sacrifices an artifact or enchantment of their choice.

Wizard Class

(Gain the next level as a sorcery to add its ability.)
You have no maximum hand size.
{2}{U}: Level 2
When this Class becomes level 2, draw two cards.
{4}{U}: Level 3
Whenever you draw a card, put a +1/+1 counter on target creature you control.

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Misty Rainforest

{T}, Pay 1 life, Sacrifice Misty Rainforest: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

Fabled Passage

{T}, Sacrifice Fabled Passage: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

Defiler of Dreams

Flying
As an additional cost to cast blue permanent spells, you may pay 2 life. Those spells cost {U} less to cast if you paid life this way. This effect reduces only the amount of blue mana you pay.
Whenever you cast a blue permanent spell, draw a card.

Arcane Signet

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

Eternal Witness

When Eternal Witness enters, you may return target card from your graveyard to your hand.

Command Tower

Druid of Purification

When Druid of Purification enters, starting with you, each player may choose an artifact or enchantment you don't control. Destroy each permanent chosen this way.

Fertilid

Fertilid enters with two +1/+1 counters on it.
{1}{G}, Remove a +1/+1 counter from Fertilid: Target player searches their library for a basic land card, puts it onto the battlefield tapped, then shuffles.

Branching Evolution

If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on that creature instead.

Skyshroud Claim

Search your library for up to two Forest cards, put them onto the battlefield, then shuffle.

Vorinclex, Monstrous Raider

Trample, haste
If you would put one or more counters on a permanent or player, put twice that many of each of those kinds of counters on that permanent or player instead.
If an opponent would put one or more counters on a permanent or player, they put half that many of each of those kinds of counters on that permanent or player instead, rounded down.

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.)

Tyrant Guard

Ravenous (This creature enters with X +1/+1 counters on it. If X is 5 or more, draw a card when it enters.)
Shieldwall — Sacrifice Tyrant Guard: Creatures you control with counters on them gain hexproof and indestructible until end of turn.

Body of Research

Create a 0/0 green and blue Fractal creature token. Put X +1/+1 counters on it, where X is the number of cards in your library.

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.

Rhystic Study

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

Take

Remove all +1/+1 counters from target creature you control. Draw that many cards.
Fuse (You may cast one or both halves of this card from your hand.)

Give

Put three +1/+1 counters on target creature.
Fuse (You may cast one or both halves of this card from your hand.)

Give // Take

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Prime Speaker Zegana

Prime Speaker Zegana enters with X +1/+1 counters on it, where X is the greatest power among other creatures you control.
When Prime Speaker Zegana enters, draw cards equal to its power.

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.)

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.)

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Fathom Mage

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever a +1/+1 counter is put on Fathom Mage, you may draw a card.

Pongify

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

Benevolent Hydra

Benevolent Hydra enters with X +1/+1 counters on it.
If one or more +1/+1 counters would be put on another creature you control, that many plus one +1/+1 counters are put on it instead.
{T}, Remove a +1/+1 counter from Benevolent Hydra: Put a +1/+1 counter on another target creature you control.

Elvish Mystic

Managorger Hydra

Trample
Whenever a player casts a spell, put a +1/+1 counter on Managorger Hydra.

Duskshell Crawler

When Duskshell Crawler enters, put a +1/+1 counter on target creature.
Each creature you control with a +1/+1 counter on it has trample. (It can deal excess combat damage to the player or planeswalker it's attacking.)

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.

Llanowar Elves

Clamavus

Proclamator Hailer — Each creature you control gets +1/+1 for each +1/+1 counter on it.

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Breeding Pool

({T}: Add {G} or {U}.)
As Breeding Pool enters, you may pay 2 life. If you don't, it enters tapped.

Rishkar, Peema Renegade

When Rishkar, Peema Renegade enters, put a +1/+1 counter on each of up to two target creatures.
Each creature you control with a counter on it has "{T}: Add {G}."

Biophagus

Genomic Enhancement — {T}: Add one mana of any color. If this mana is spent to cast a creature spell, that creature enters with an additional +1/+1 counter on it.

Island

Vigor

Trample
If damage would be dealt to another creature you control, prevent that damage. Put a +1/+1 counter on that creature for each 1 damage prevented this way.
When Vigor is put into a graveyard from anywhere, shuffle it into its owner's library.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Rapid Hybridization

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

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.)

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.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Herald of Secret Streams

Creatures you control with +1/+1 counters on them can't be blocked.

Force of Negation

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost.
Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Boseiju, Who Endures

{T}: Add {G}.
Channel — {1}{G}, Discard Boseiju, Who Endures: Destroy target artifact, enchantment, or nonbasic land an opponent controls. That player may search their library for a land card with a basic land type, put it onto the battlefield, then shuffle. This ability costs {1} less to activate for each legendary creature you control.