Entrancing Melody

Gain control of target creature with mana value X.

Hangarback Walker

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

Channel

Until end of turn, any time you could activate a mana ability, you may pay 1 life. If you do, add {C}.

Yavimaya Bloomsage

At the beginning of your end step, put a +1/+1 counter on target creature you control. Then if that creature has power 7 or greater, this creature becomes prepared. (While it's prepared, you may cast a copy of its spell. Doing so unprepares it.)

Yavimaya Bloomsage // Channel

Pull from Tomorrow

Doppelgang

For each of X target permanents, create X tokens that are copies of that permanent.

Open the Way

X can't be greater than the number of players in the game.
Reveal cards from the top of your library until you reveal X land cards. Put those land cards onto the battlefield tapped and the rest on the bottom of your library in a random order.

Counterspell

Power Sink

Counter target spell unless its controller pays {X}. If that player doesn't, they tap all lands with mana abilities they control and lose all unspent mana.

Altered Ego

This spell can't be countered.
You may have this creature enter as a copy of any creature on the battlefield, except it enters with X additional +1/+1 counters on it.

Deekah, Fractal Theorist

Magecraft — Whenever you cast or copy an instant or sorcery spell, create a 0/0 green and blue Fractal creature token. Put X +1/+1 counters on it, where X is that spell's mana value.
{3}{U}: Target creature token can't be blocked this turn.

Nexus Mentality

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Move all counters from target nonland permanent you control onto another target nonland permanent you control.
• Remove all counters from target nonland permanent you control. Draw a card for each counter removed this way.

Mathemagics

Target player draws 2ˣ cards. (2º = 1, 2¹ = 2, 2² = 4, 2³ = 8, 2⁴ = 16, 2⁵ = 32, and so on.)

Tyvar's Stand

Target creature you control gets +X/+X and gains hexproof and indestructible until end of turn. (It can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)

Biomass Mutation

Creatures you control have base power and toughness X/X until end of turn.

Wan Shi Tong, Librarian

Flash
Flying, vigilance
When Wan Shi Tong enters, put X +1/+1 counters on him. Then draw half X cards, rounded down.
Whenever an opponent searches their library, put a +1/+1 counter on Wan Shi Tong and draw a card.

Fractal Harness

When this Equipment enters, create a 0/0 green and blue Fractal creature token. Put X +1/+1 counters on it and attach this Equipment to it.
Whenever equipped creature attacks, double the number of +1/+1 counters on it.
Equip {2}

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.

Mockingbird

Flying
You may have this creature enter as a copy of any creature on the battlefield with mana value less than or equal to the amount of mana spent to cast this creature, except it's a Bird in addition to its other types and it has flying.

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.

Troyan, Gutsy Explorer

{T}: Add {G}{U}. Spend this mana only to cast spells with mana value 5 or greater or spells with {X} in their mana costs.
{U}, {T}: Draw a card, then discard a card.

Zimone, All-Questioning

At the beginning of your end step, if a land entered the battlefield under your control this turn and you control a prime number of lands, create Primo, the Indivisible, a legendary 0/0 green and blue Fractal creature token, then put that many +1/+1 counters on it. (2, 3, 5, 7, 11, 13, 17, 19, 23, 29, and 31 are prime numbers.)

Turbulent Wilderness

({T}: Add {G} or {U}.)
This land enters tapped unless your opponents control eight or more lands.

Fabled Passage

{T}, Sacrifice this land: 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.

Open into Wonder

X target creatures can't be blocked this turn. Until end of turn, those creatures gain "Whenever this creature deals combat damage to a player, draw a card."

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.

Zimone, Infinite Analyst

The first spell you cast with {X} in its mana cost each turn costs {1} less to cast for each +1/+1 counter on Zimone.
Whenever you cast your first spell with {X} in its mana cost each turn, put two +1/+1 counters on Zimone.

Study Hall

{T}: Add {C}.
{1}, {T}: Add one mana of any color. When you spend this mana to cast your commander, scry X, where X is the number of times it's been cast from the command zone this game.

Primordial Hydra

This creature enters with X +1/+1 counters on it.
At the beginning of your upkeep, double the number of +1/+1 counters on this creature.
This creature has trample as long as it has ten or more +1/+1 counters on it.

Stonecoil Serpent

Reach, trample, protection from multicolored
This creature enters with X +1/+1 counters on it.

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 this creature: Creatures you control with counters on them gain hexproof and indestructible until end of turn.

Oversimplify

Exile all creatures. Each player creates a 0/0 green and blue Fractal creature token and puts a number of +1/+1 counters on it equal to the total power of creatures they controlled that were exiled this way.

Silkguard

Put a +1/+1 counter on each of up to X target creatures you control.
Auras, Equipment, and modified creatures you control gain hexproof until end of turn. (Equipment, Auras you control, and counters are modifications.)

Hydroid Krasis

When you cast this spell, you gain half X life and draw half X cards. Round down each time.
Flying, trample
This creature enters with X +1/+1 counters on it.

Tangled Islet

({T}: Add {G} or {U}.)
This land enters tapped.

Guardian Augmenter

Flash
Commander creatures you control get +2/+2.
Commanders you control have hexproof.

Nature's Lore

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

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Quandrix Charm

Choose one —
• Counter target spell unless its controller pays {2}.
• Destroy target enchantment.
• Target creature has base power and toughness 5/5 until end of turn.

Vineglimmer Snarl

As this land enters, you may reveal a Forest or Island card from your hand. If you don't, this land enters tapped.
{T}: Add {G} or {U}.

Brass Infiniscope

{T}: Add {C}{C}. When you next cast a spell with {X} in its mana cost this turn, you draw a card and gain half X life, rounded down.

Grove's Bounty

Distribute X +1/+1 counters among any number of target creatures you control. (Then exile this card. You may cast the creature later from exile.)

Elusive Otter

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Creatures with power less than this creature's power can't block it.

Elusive Otter // Grove's Bounty

Ravener

Flash
Ravenous (This creature enters with X +1/+1 counters on it. If X is 5 or more, draw a card when it enters.)
When this creature enters, target creature attacks target opponent this turn if able.

Flooded Grove

{T}: Add {C}.
{G/U}, {T}: Add {G}{G}, {G}{U}, or {U}{U}.

Zimone's Hypothesis

You may put a +1/+1 counter on a creature. Then choose odd or even. Return each creature with power of the chosen quality to its owner's hand. (Zero is even.)

Stroke of Genius

Beast Within

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

Sol Ring

Lifeblood Hydra

Trample
This creature enters with X +1/+1 counters on it.
When this creature dies, you gain life and draw cards equal to its power.

Syncopate

Counter target spell unless its controller pays {X}. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Owlin Spiralmancer

Flying, vigilance
Whenever you cast your first spell with {X} in its mana cost each turn, you may copy it. You may choose new targets for the copy. (A copy of a permanent spell becomes a token.)

Rapid Hybridization

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

Hinterland Harbor

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

Island

Quandrix Campus

This land enters tapped.
{T}: Add {G} or {U}.
{4}, {T}: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Goldvein Hydra

Vigilance, trample, haste
This creature enters with X +1/+1 counters on it.
When this creature dies, create a number of tapped Treasure tokens equal to its power.

Primal Might

Target creature you control gets +X/+X until end of turn. Then it fights up to one target creature you don't control. (Each deals damage equal to its power to the other.)

Mass Manipulation

Gain control of X target creatures and/or planeswalkers.

Path of Ancestry

This land enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Expansion Algorithm

Proliferate X times. (To proliferate, choose any number of permanents and/or players, then give each another counter of each kind already there.)

Forest

Sodden Verdure

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

Mana Bloom

This enchantment enters with X charge counters on it.
Remove a charge counter from this enchantment: Add one mana of any color. Activate only once each turn.
At the beginning of your upkeep, if this enchantment has no charge counters on it, return it to its owner's hand.

Rain-Slicked Copse

({T}: Add {G} or {U}.)
This land enters tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

Paradox Gardens

This land enters tapped.
{T}: Add {G} or {U}.
{2}{G}{U}, {T}: Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Quandrix Command

Choose two —
• Return target creature or planeswalker to its owner's hand.
• Counter target artifact or enchantment spell.
• Put two +1/+1 counters on target creature.
• Target player shuffles up to three target cards from their graveyard into their library.

Zimone, Quandrix Prodigy

{1}, {T}: You may put a land card from your hand onto the battlefield tapped.
{4}, {T}: Draw a card. If you control eight or more lands, draw two cards instead.

Alchemist's Refuge

{T}: Add {C}.
{G}{U}, {T}: You may cast spells this turn as though they had flash.

Lost in the Maze

Flash
When this enchantment enters, tap X target creatures. Put a stun counter on each of those creatures you don't control. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Tapped creatures you control have hexproof.

Kinetic Ooze

This creature enters with X +1/+1 counters on it.
When this creature enters, destroy up to one target artifact or enchantment with mana value X or less. If X is 5 or more, you draw a card. If X is 10 or more, double the number of +1/+1 counters on any number of other target creatures.

Run the Play

Put a +1/+1 counter on each of up to X target creatures. Those creatures gain flying until end of turn. Draw a card.

Striding Shotcaller

Reach
Whenever one or more creatures you control deal combat damage to a player, this creature becomes prepared. (While it's prepared, you may cast a copy of its spell. Doing so unprepares it.)

Striding Shotcaller // Run the Play

Lattice Library

This enchantment enters with X study counters on it.
When this enchantment enters and whenever you cast your first spell with {X} in its mana cost each turn, create a 0/0 green and blue Fractal creature token. Put a number of +1/+1 counters on it equal to the number of study counters on this enchantment.

Quandrix Apprentice

Magecraft — Whenever you cast or copy an instant or sorcery spell, look at the top three cards of your library. You may reveal a land card from among them and put that card into your hand. Put the rest on the bottom of your library in any order.

Steelbane Hydra

This creature enters with X +1/+1 counters on it.
{2}{G}, Remove a +1/+1 counter from this creature: Destroy target artifact or enchantment.

Terramorphic Expanse

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

Curse of the Swine

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

Animist's Awakening

Reveal the top X cards of your library. Put all land cards from among them onto the battlefield tapped and the rest on the bottom of your library in a random order.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, untap those lands.

Oran-Rief, the Vastwood

This land enters tapped.
{T}: Add {G}.
{T}: Put a +1/+1 counter on each green creature that entered this turn.

Commander's Insight

Target player draws X cards plus an additional card for each time they've cast a commander from the command zone this game.

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Forgotten Ancient

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

Perplexing Test

Choose one —
• Return all creature tokens to their owners' hands.
• Return all nontoken creatures to their owners' hands.

Elementalist's Palette

Whenever you cast a spell with {X} in its mana cost, put two charge counters on this artifact.
{T}: Add one mana of any color.
{T}: Add {C} for each charge counter on this artifact. Spend this mana only on costs that contain {X}.

Condescend

Counter target spell unless its controller pays {X}. Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Yavimaya Coast

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

Stumpsquall Hydra

When this creature enters, distribute X +1/+1 counters among it and any number of commanders.

March of Swirling Mist

As an additional cost to cast this spell, you may exile any number of blue cards from your hand. This spell costs {2} less to cast for each card exiled this way.
Up to X target creatures phase out. (While they're phased out, they're treated as though they don't exist. Each one phases in before its controller untaps during their next untap step.)

The Goose Mother

Flying
The Goose Mother enters with X +1/+1 counters on it.
When The Goose Mother enters, create half X Food tokens, rounded up.
Whenever The Goose Mother attacks, you may sacrifice a Food. If you do, draw a card.

Arcane Signet

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

Eureka Moment

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

Rampaging Yao Guai

Vigilance, trample
This creature enters with X +1/+1 counters on it.
When this creature enters, destroy any number of target artifacts and/or enchantments with total mana value X or less.

Primo, the Unbounded

Trample
Primo enters with twice X +1/+1 counters on it.
Whenever one or more creatures you control with base power 0 deal combat damage to a player, create a 0/0 green and blue Fractal creature token. Put a number of +1/+1 counters on it equal to the damage dealt.

Unbound Flourishing

Whenever you cast a permanent spell with a mana cost that contains {X}, double the value of X.
Whenever you cast an instant or sorcery spell or activate an ability, if that spell's mana cost or that ability's activation cost contains {X}, copy that spell or ability. You may choose new targets for the copy.

Nev, the Practical Dean

Creatures you control with counters on them have trample.
Whenever you cast your first spell with {X} in its mana cost each turn, put X +1/+1 counters on Nev.

Overflowing Basin

Three Visits

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

Reliquary Tower

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

Finale of Revelation

Draw X cards. If X is 10 or more, instead shuffle your graveyard into your library, draw X cards, untap up to five lands, and you have no maximum hand size for the rest of the game.
Exile Finale of Revelation.

Benevolent Hydra

This creature 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 this creature: Put a +1/+1 counter on another target creature you control.

Exotic Orchard

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