Have

Walking Ballista

This creature enters with X +1/+1 counters on it.
{4}: Put a +1/+1 counter on this creature.
Remove a +1/+1 counter from this creature: It deals 1 damage to any target.

Getting

Ripples of Potential

Proliferate, then choose any number of permanents you control that had a counter put on them this way. Those permanents phase out. (To proliferate, choose any number of permanents and/or players, then give each another counter of each kind already there. Treat phased-out permanents and anything attached to them as though they don't exist until their controller's next turn.)

Bane of Progress

When this creature enters, destroy all artifacts and enchantments. Put a +1/+1 counter on this creature for each permanent destroyed this way.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Brushland

{T}: Add {C}.
{T}: Add {G} or {W}. This land deals 1 damage to you.

Seaside Citadel

This land enters tapped.
{T}: Add {G}, {W}, or {U}.

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.)

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.

Sovereign Okinec Ahau

Ward {2}
Whenever Sovereign Okinec Ahau attacks, for each creature you control with power greater than that creature's base power, put a number of +1/+1 counters on that creature equal to the difference.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Warden of the Grove

At the beginning of your end step, put a +1/+1 counter on this creature.
Whenever another nontoken creature you control enters, it endures X, where X is the number of counters on this creature. (Put X +1/+1 counters on the creature that entered or create an X/X white Spirit creature token.)

Birds of Paradise

Dreamtide Whale

Vanishing 2 (This creature enters with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a player casts their second spell each turn, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Glacial Fortress

This land enters tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Forest

Spara's Headquarters

({T}: Add {G}, {W}, or {U}.)
This land enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Marcus, Mutant Mayor

Vigilance, trample
Whenever a creature you control deals combat damage to a player, draw a card if that creature has a +1/+1 counter on it. If it doesn't, put a +1/+1 counter on it.

Noble Hierarch

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
{T}: Add {G}, {W}, or {U}.

Dovin's Veto

This spell can't be countered.
Counter target noncreature spell.

Sol Ring

Grateful Apparition

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

Flawless Maneuver

If you control a commander, you may cast this spell without paying its mana cost.
Creatures you control gain indestructible until end of turn.

Arcane Signet

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

Command Tower

Skycloud Expanse

Mutational Advantage

Permanents you control with counters on them gain hexproof and indestructible until end of turn. Prevent all damage that would be dealt to those permanents this turn. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Yavimaya Coast

{T}: Add {C}.
{T}: Add {G} or {U}. This land deals 1 damage to you.

Chocobo Knights

Whenever you attack, creatures you control with counters on them gain double strike until end of turn.

Fierce Guardianship

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

Swan Song

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

Auron, Venerated Guardian

Vigilance
Shooting Star — Whenever Auron attacks, put a +1/+1 counter on it. When you do, exile target creature defending player controls with power less than Auron's power until Auron leaves the battlefield.

Ingenious Prodigy

Skulk (This creature can't be blocked by creatures with greater power.)
This creature enters with X +1/+1 counters on it.
At the beginning of your upkeep, if this creature has one or more +1/+1 counters on it, you may remove a +1/+1 counter from it. If you do, draw a card.

Canopy Vista

({T}: Add {G} or {W}.)
This land enters tapped unless you control two or more basic lands.

Wave Goodbye

Return each creature without a +1/+1 counter on it to its owner's hand.

Collective Effort

Escalate—Tap an untapped creature you control. (Pay this cost for each mode chosen beyond the first.)
Choose one or more —
• Destroy target creature with power 4 or greater.
• Destroy target enchantment.
• Put a +1/+1 counter on each creature target player controls.

Damning Verdict

Destroy all creatures with no counters on them.

Hinterland Harbor

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

Hallowed Fountain

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

Adarkar Wastes

{T}: Add {C}.
{T}: Add {W} or {U}. This land deals 1 damage to you.

Dreamroot Cascade

This land enters tapped unless you control two or more other lands.
{T}: Add {G} or {U}.

Luminous Broodmoth

Flying
Whenever a creature you control without flying dies, return it to the battlefield under its owner's control with a flying counter on it.

Crystalline Giant

At the beginning of combat on your turn, choose a kind of counter at random that this creature doesn't have on it from among flying, first strike, deathtouch, hexproof, lifelink, menace, reach, trample, vigilance, and +1/+1. Put a counter of that kind on this creature.

Windswept Heath

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

Incubation Druid

{T}: Add one mana of any type that a land you control could produce. If this creature has a +1/+1 counter on it, add three mana of that type instead.
{3}{G}{G}: Adapt 3. (If this creature has no +1/+1 counters on it, put three +1/+1 counters on it.)

Arwen, Mortal Queen

Arwen enters with an indestructible counter on it.
{1}, Remove an indestructible counter from Arwen: Another target creature gains indestructible until end of turn. Put a +1/+1 counter and a lifelink counter on that creature and a +1/+1 counter and a lifelink counter on Arwen.

Lae'zel, Vlaakith's Champion

If you would put one or more counters on a creature or planeswalker you control or on yourself, put that many plus one of each of those kinds of counters on that permanent or player instead.
Choose a Background (You can have a Background as a second commander.)

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 this enchantment.
At the beginning of your upkeep, if this enchantment has twenty or more growth counters on it, you win the game.

Breeding Pool

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

Innkeeper's Talent

(Gain the next level as a sorcery to add its ability.)
At the beginning of combat on your turn, put a +1/+1 counter on target creature you control.
{G}: Level 2
Permanents you control with counters on them have ward {1}.
{3}{G}: Level 3
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.

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 this creature.

Heronblade Elite

Vigilance
Whenever another Human you control enters, put a +1/+1 counter on this creature.
{T}: Add X mana of any one color, where X is this creature's power.

Gatta and Luzzu

Flash
When Gatta and Luzzu enters, choose target creature you control. If damage would be dealt to that creature this turn, prevent that damage and put that many +1/+1 counters on it.

Luminarch Aspirant

At the beginning of combat on your turn, put a +1/+1 counter on target creature you control.

Flooded Strand

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

Kami of Whispered Hopes

If one or more +1/+1 counters would be put on a permanent you control, that many plus one +1/+1 counters are put on that permanent instead.
{T}: Add X mana of any one color, where X is this creature's power.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Ezuri, Stalker of Spheres

When Ezuri enters, you may pay {3}. If you do, proliferate twice.
Whenever you proliferate, draw a card.

Sphere Grid

Whenever a creature you control deals combat damage to a player, put a +1/+1 counter on that creature.
Unlock Ability — Creatures you control with +1/+1 counters on them have reach and trample.

Sunpetal Grove

This land enters tapped unless you control a Forest or a Plains.
{T}: Add {G} or {W}.

Temple Garden

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

Falco Spara, Pactweaver

Flying, trample
Falco Spara enters with a shield counter on it.
You may look at the top card of your library any time.
You may cast spells from the top of your library by removing a counter from a creature you control in addition to paying their other costs.

Kutzil, Malamet Exemplar

Your opponents can't cast spells during your turn.
Whenever one or more creatures you control each with power greater than its base power deals combat damage to a player, draw a card.

Misty Rainforest

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

Rejuvenating Springs

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

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Maester Seymour

At the beginning of combat on your turn, put a number of +1/+1 counters equal to Maester Seymour's power on another target creature you control.
{3}{G}{G}: Monstrosity X, where X is the number of counters among creatures you control. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)

Plains

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.

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. ({U/P} can be paid with either {U} or 2 life.)

Summon: Magus Sisters

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II, III — Choose one at random —
• Combine Powers! — Put three +1/+1 counters on target creature.
• Defense! — Put a shield counter on target creature. You gain 3 life.
• Fight! — This creature fights up to one target creature an opponent controls.
Haste

Tromell, Seymour's Butler

Each other nontoken creature you control enters with an additional +1/+1 counter on it.
{1}, {T}: Proliferate X times, where X is the number of nontoken creatures you control that entered this turn. (To proliferate, choose any number of permanents and/or players, then give each another counter of each kind already there.)

Bountiful Promenade

This land enters tapped unless you have two or more opponents.
{T}: Add {G} or {W}.

Master Biomancer

Each other creature you control enters with a number of additional +1/+1 counters on it equal to this creature's power and as a Mutant in addition to its other types.

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.

Myojin of Cleansing Fire

Myojin of Cleansing Fire enters with a divinity counter on it if you cast it from your hand.
Myojin of Cleansing Fire has indestructible as long as it has a divinity counter on it.
Remove a divinity counter from Myojin of Cleansing Fire: Destroy all other creatures.

Sea of Clouds

This land enters tapped unless you have two or more opponents.
{T}: Add {W} or {U}.

Nesting Grounds

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

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 this creature, you may draw a card.

Replicating Ring

{T}: Add one mana of any color.
At the beginning of your upkeep, put a night counter on this artifact. 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."

Brokers Ascendancy

At the beginning of your end step, put a +1/+1 counter on each creature you control and a loyalty counter on each planeswalker you control.

Ozolith, the Shattered Spire

If one or more +1/+1 counters would be put on an artifact or creature you control, that many plus one +1/+1 counters are put on it instead.
{1}{G}, {T}: Put a +1/+1 counter on target artifact or creature you control. Activate only as a sorcery.
Cycling {2} ({2}, Discard this card: Draw a card.)

Slippery Bogbonder

Flash
Hexproof
When this creature enters, put a hexproof counter on target creature. Then move any number of counters from among creatures you control onto that creature.

Pollywog Prodigy

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 an opponent casts a noncreature spell with mana value less than this creature's power, draw a card.

Yuna, Grand Summoner

Grand Summon — {T}: Add one mana of any color. When you next cast a creature spell this turn, that creature enters with two additional +1/+1 counters on it.
Whenever another permanent you control is put into a graveyard from the battlefield, if it had one or more counters on it, you may put that number of +1/+1 counters on target creature.

O'aka, Traveling Merchant

{T}, Remove a counter from a nonland permanent you control: Draw a card.

Tidus, Yuna's Guardian

At the beginning of combat on your turn, you may move a counter from target creature you control onto a second target creature you control.
Cheer — Whenever one or more creatures you control with counters on them deal combat damage to a player, you may draw a card and proliferate. Do this only once each turn.

Kodama of the West Tree

Reach
Modified creatures you control have trample. (Equipment, Auras you control, and counters are modifications.)
Whenever a modified creature you control deals combat damage to a player, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Island

Thrummingbird

Flying
Whenever this creature 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.)

Sungrass Prairie

Rhystic Study

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

Generous Pup

Vigilance
Whenever one or more +1/+1 counters are put on this creature, put a +1/+1 counter on each other creature you control. This ability triggers only once each turn.

Shelinda, Yevon Acolyte

Lifelink
Whenever another creature you control enters, put a +1/+1 counter on that creature if its power is less than Shelinda's power. Otherwise, put a +1/+1 counter on Shelinda.

Sin, Unending Cataclysm

Flying, trample
As Sin enters, remove all counters from any number of artifacts, creatures, and enchantments. Sin enters with X +1/+1 counters on it, where X is twice the number of counters removed this way.
When Sin dies, put its counters on target creature you control, then shuffle this card into its owner's library.

Deserted Beach

This land enters tapped unless you control two or more other lands.
{T}: Add {W} or {U}.

Mikaeus, the Lunarch

Mikaeus enters with X +1/+1 counters on it.
{T}: Put a +1/+1 counter on Mikaeus.
{T}, Remove a +1/+1 counter from Mikaeus: Put a +1/+1 counter on each other creature you control.

Herald of Secret Streams

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

The Earth Crystal

Green spells you cast cost {1} less to cast.
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.
{4}{G}{G}, {T}: Distribute two +1/+1 counters among one or two target creatures you control.

Kimahri, Valiant Guardian

Vigilance
Ronso Rage — At the beginning of combat on your turn, put a +1/+1 counter on Kimahri and tap target creature an opponent controls. Then you may have Kimahri become a copy of that creature, except its name is Kimahri, Valiant Guardian and it has vigilance and this ability.

Myojin of Towering Might

Myojin of Towering Might enters with an indestructible counter on it if you cast it from your hand.
Remove an indestructible counter from Myojin of Towering Might: Distribute eight +1/+1 counters among any number of target creatures you control. They gain trample until end of turn.

Astral Cornucopia

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

Summon: Yojimbo

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after IV.)
I — Exile target artifact, enchantment, or tapped creature an opponent controls.
II, III — Until your next turn, creatures can't attack you unless their controller pays {2} for each of those creatures.
IV — Create X Treasure tokens, where X is the number of opponents who control a creature with power 4 or greater.
Vigilance

Reluctant Role Model

Survival — At the beginning of your second main phase, if this creature is tapped, put a flying, lifelink, or +1/+1 counter on it.
Whenever this creature or another creature you control dies, if it had counters on it, put those counters on up to one target creature.

Bred for the Hunt

Whenever a creature you control with a +1/+1 counter on it deals combat damage to a player, you may draw a card.