Gift of the Viper

Put a +1/+1 counter, a reach counter, and a deathtouch counter on target creature. Untap it.

Illvoi Galeblade

Flash
Flying
{2}, Sacrifice this creature: Draw a card.

Herald of Secret Streams

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

Invigorating Surge

Put a +1/+1 counter on target creature you control, then double the number of +1/+1 counters on that 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.

Invigorating Hot Spring

This enchantment enters with four +1/+1 counters on it.
Modified creatures you control have haste. (Equipment, Auras you control, and counters are modifications.)
Remove a +1/+1 counter from this enchantment: Put a +1/+1 counter on target creature you control. Activate only as a sorcery and only once each turn.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Island

Ouroboroid

At the beginning of combat on your turn, put X +1/+1 counters on each creature you control, where X is this creature's power.

Mirror Gallery

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.

Broodguard Elite

This creature enters with X +1/+1 counters on it.
When this creature leaves the battlefield, put its counters on target creature you control.
Warp {X}{G} (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)

Chandra's Ignition

Target creature you control deals damage equal to its power to each other creature and each opponent.

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.)

Growth Spiral

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

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.

Sol Ring

Power Fist

Equipped creature has trample and "Whenever this creature deals combat damage to a player, put that many +1/+1 counters on it."
Equip {2}

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.)

Arcane Signet

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

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.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Temur Ascendancy

Creatures you control have haste.
Whenever a creature you control with power 4 or greater enters, you may draw a card.

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.)

Vorel of the Hull Clade

{G}{U}, {T}: Double the number of each kind of counter on target artifact, creature, or land.

Xenagos, God of Revels

Indestructible
As long as your devotion to red and green is less than seven, Xenagos isn't a creature.
At the beginning of combat on your turn, another target creature you control gains haste and gets +X/+X until end of turn, where X is that creature's power.

Mirror Box

The "legend rule" doesn't apply to permanents you control.
Each legendary creature you control gets +1/+1.
Each nontoken creature you control gets +1/+1 for each other creature you control with the same name as that creature.

Command Tower

Spectacular Showdown

Put a double strike counter on target creature, then goad each creature that had a double strike counter put on it this way. (Until your next turn, those creatures attack each combat if able and attack a player other than you if able.)
Overload {4}{R}{R}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Planetary Annihilation

Each player chooses six lands they control, then sacrifices the rest. Planetary Annihilation deals 6 damage to each creature.

Animar, Soul of Elements

Protection from white and from black
Whenever you cast a creature spell, put a +1/+1 counter on Animar.
Creature spells you cast cost {1} less to cast for each +1/+1 counter on Animar.

Beast Within

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

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.

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.

Me, the Immortal

At the beginning of combat on your turn, put your choice of a +1/+1, first strike, vigilance, or menace counter on Me.
Counters remain on Me as it moves to any zone other than a player's hand or library.
You may cast this card from your graveyard by discarding two cards in addition to paying its other costs.

Winged Hive Tyrant

Flying, haste
The Will of the Hive Mind — Other creatures you control with counters on them have flying and haste.

Tyrite Sanctum

{T}: Add {C}.
{2}, {T}: Target legendary creature becomes a God in addition to its other types. Put a +1/+1 counter on it.
{4}, {T}, Sacrifice this land: Put an indestructible counter on target God.

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Goldberry, River-Daughter

{T}: Move a counter of each kind not on Goldberry from another target permanent you control onto Goldberry.
{U}, {T}: Move one or more counters from Goldberry onto another target permanent you control. If you do, draw a card.

Rite of Replication

Kicker {5} (You may pay an additional {5} as you cast this spell.)
Create a token that's a copy of target creature. If this spell was kicked, create five of those tokens instead.

Thromok the Insatiable

Devour X, where X is the number of creatures devoured this way (As this creature enters, you may sacrifice any number of creatures. It enters with X +1/+1 counters on it for each of those creatures.)

Counterspell

Mountain

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Danny Pink

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Creatures you control have "Whenever one or more counters are put on this creature for the first time each turn, draw a card."

Hydra's Growth

Enchant creature
When this Aura enters, put a +1/+1 counter on enchanted creature.
At the beginning of your upkeep, double the number of +1/+1 counters on enchanted creature.

Uncivil Unrest

Nontoken creatures you control have riot. (They enter with your choice of a +1/+1 counter or haste.)
If a creature you control with a +1/+1 counter on it would deal damage to a permanent or player, it deals double that damage instead.

Sakashima of a Thousand Faces

You may have Sakashima enter as a copy of another creature you control, except it has Sakashima's other abilities.
The "legend rule" doesn't apply to permanents you control.
Partner (You can have two commanders if both have partner.)

Kodama's Reach

Frontier Bivouac

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

Terrasymbiosis

Whenever you put one or more +1/+1 counters on a creature you control, you may draw that many cards. Do this only once each turn.

Shattered Wings

Destroy target artifact, enchantment, or creature with flying. Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Ketria Triome

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

Negate

Deepglow Skate

When this creature enters, double the number of each kind of counter on any number of target permanents.

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.