Kangee, Aerie Keeper

Kicker {X}{2} (You may pay an additional {X}{2} as you cast this spell.)
Flying
When Kangee, Aerie Keeper enters, if it was kicked, put X feather counters on it.
Other Bird creatures get +1/+1 for each feather counter on Kangee, Aerie Keeper.

Endless One

Endless One enters with X +1/+1 counters on it.

Voodoo Doll

At the beginning of your upkeep, put a pin counter on Voodoo Doll.
At the beginning of your end step, if Voodoo Doll is untapped, destroy Voodoo Doll and it deals damage to you equal to the number of pin counters on it.
{X}{X}, {T}: Voodoo Doll deals damage equal to the number of pin counters on it to any target. X is the number of pin counters on Voodoo Doll.

Ent-Draught Basin

{X}, {T}: Put a +1/+1 counter on target creature with power X. Activate only as a sorcery.

Atalya, Samite Master

{X}, {T}: Choose one —
• Prevent the next X damage that would be dealt to target creature this turn. Spend only white mana on X.
• You gain X life. Spend only white mana on X.

Hail of Arrows

Hail of Arrows deals X damage divided as you choose among any number of target attacking creatures.

Swell of Courage

Creatures you control get +2/+2 until end of turn.
Reinforce X—{X}{W}{W} ({X}{W}{W}, Discard this card: Put X +1/+1 counters on target creature.)

Chimeric Mass

Chimeric Mass enters with X charge counters on it.
{1}: Until end of turn, Chimeric Mass becomes a Construct artifact creature with "This creature's power and toughness are each equal to the number of charge counters on it."

Selective Snare

Return X target creatures of the creature type of your choice to their owner's hand.

Vengeful Archon

Flying
{X}: Prevent the next X damage that would be dealt to you this turn. If damage is prevented this way, Vengeful Archon deals that much damage to target player or planeswalker.

Phyrexian Marauder

Phyrexian Marauder enters with X +1/+1 counters on it.
Phyrexian Marauder can't block.
Phyrexian Marauder can't attack unless you pay {1} for each +1/+1 counter on it.

Occult Epiphany

Draw X cards, then discard X cards. Create a 1/1 white Spirit creature token with flying for each card type among cards discarded this way.

Venarian Glimmer

Target player reveals their hand. You choose a nonland card with mana value X or less from it. That player discards that card.

Transmute Artifact

Sacrifice an artifact. If you do, search your library for an artifact card. If that card's mana value is less than or equal to the sacrificed artifact's mana value, put it onto the battlefield. If it's greater, you may pay {X}, where X is the difference. If you do, put it onto the battlefield. If you don't, put it into its owner's graveyard. Then shuffle.

Linessa, Zephyr Mage

{X}{U}{U}, {T}: Return target creature with mana value X to its owner's hand.
Grandeur — Discard another card named Linessa, Zephyr Mage: Target player returns a creature they control to its owner's hand, then repeats this process for an artifact, an enchantment, and a land.

Lin Sivvi, Defiant Hero

{X}, {T}: Search your library for a Rebel permanent card with mana value X or less, put it onto the battlefield, then shuffle.
{3}: Put target Rebel card from your graveyard on the bottom of your library.

Folio of Fancies

Players have no maximum hand size.
{X}{X}, {T}: Each player draws X cards.
{2}{U}, {T}: Each opponent mills cards equal to the number of cards in their hand.

Blue Sun's Zenith

Target player draws X cards. Shuffle Blue Sun's Zenith into its owner's library.

Disrupting Shoal

You may exile a blue card with mana value X from your hand rather than pay this spell's mana cost.
Counter target spell if its mana value is X.

Even the Score

This spell costs {U}{U}{U} less to cast if an opponent has drawn four or more cards this turn.
Draw X cards.

Snake Basket

{X}, Sacrifice Snake Basket: Create X 1/1 green Snake creature tokens. Activate only as a sorcery.

Finale of Glory

Create X 2/2 white Soldier creature tokens with vigilance. If X is 10 or more, also create X 4/4 white Angel creature tokens with flying and vigilance.

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.

Winter's Chill

Cast this spell only during combat before blockers are declared.
X can't be greater than the number of snow lands you control.
Choose X target attacking creatures. For each of those creatures, its controller may pay {1} or {2}. If that player doesn't, destroy that creature at end of combat. If that player pays only {1}, prevent all combat damage that would be dealt to and dealt by that creature this combat.

Mikaeus, the Lunarch

Mikaeus, the Lunarch 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.

Synod Artificer

{X}, {T}: Tap X target noncreature artifacts.
{X}, {T}: Untap X target noncreature artifacts.

Defenders of Humanity

When Defenders of Humanity enters, create X 2/2 white Astartes Warrior creature tokens with vigilance.
{X}{2}{W}, Exile Defenders of Humanity: Create X 2/2 white Astartes Warrior creature tokens with vigilance. Activate only if you control no creatures and only during your turn.

Increasing Confusion

Target player mills X cards. If this spell was cast from a graveyard, that player mills twice that many cards instead.
Flashback {X}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Hazduhr the Abbot

{X}, {T}: The next X damage that would be dealt this turn to target white creature you control is dealt to Hazduhr the Abbot instead.

Empty the Laboratory

Sacrifice X Zombies, then reveal cards from the top of your library until you reveal a number of Zombie creature cards equal to the number of Zombies sacrificed this way. Put those cards onto the battlefield and the rest on the bottom of your library in a random order.

Sweep the Skies

Converge — Create a 1/1 colorless Thopter artifact creature token with flying for each color of mana spent to cast this spell.

Ice Cauldron

{X}, {T}: You may exile a nonland card from your hand. You may cast that card for as long as it remains exiled. Put a charge counter on Ice Cauldron and note the type and amount of mana spent to pay this activation cost. Activate only if there are no charge counters on Ice Cauldron.
{T}, Remove a charge counter from Ice Cauldron: Add Ice Cauldron's last noted type and amount of mana. Spend this mana only to cast the last card exiled with Ice Cauldron.

Azor, the Lawbringer

Flying
When Azor, the Lawbringer enters, each opponent can't cast instant or sorcery spells during that player's next turn.
Whenever Azor attacks, you may pay {X}{W}{U}{U}. If you do, you gain X life and draw X cards.

Whetwheel

{X}{X}, {T}: Target player mills X cards.
Morph {3} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Icy Blast

Tap X target creatures.
Ferocious — If you control a creature with power 4 or greater, those creatures don't untap during their controllers' next untap steps.

Transcendent Message

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Draw X cards.

Clockwork Steed

Clockwork Steed enters with four +1/+0 counters on it.
Clockwork Steed can't be blocked by artifact creatures.
At end of combat, if Clockwork Steed attacked or blocked this combat, remove a +1/+0 counter from it.
{X}, {T}: Put up to X +1/+0 counters on Clockwork Steed. This ability can't cause the total number of +1/+0 counters on Clockwork Steed to be greater than four. Activate only during your upkeep.

Reshape

As an additional cost to cast this spell, sacrifice an artifact.
Search your library for an artifact card with mana value X or less, put it onto the battlefield, then shuffle.

Overrule

Counter target spell unless its controller pays {X}. You gain X life.

Universal Surveillance

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Draw X cards.

March of Otherworldly Light

As an additional cost to cast this spell, you may exile any number of white cards from your hand. This spell costs {2} less to cast for each card exiled this way.
Exile target artifact, creature, or enchantment with mana value X or less.

Vigil for the Lost

Whenever a creature you control dies, you may pay {X}. If you do, you gain X life.

Shifting Wall

Defender (This creature can't attack.)
Shifting Wall enters with X +1/+1 counters on it.

Clockwork Avian

Flying
Clockwork Avian enters with four +1/+0 counters on it.
At end of combat, if Clockwork Avian attacked or blocked this combat, remove a +1/+0 counter from it.
{X}, {T}: Put up to X +1/+0 counters on Clockwork Avian. This ability can't cause the total number of +1/+0 counters on Clockwork Avian to be greater than four. Activate only during your upkeep.

Prismatic Ending

Converge — Exile target nonland permanent if its mana value is less than or equal to the number of colors of mana spent to cast this spell.

Vitality Hunter

Lifelink
{X}{W}{W}: Monstrosity X. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)
When Vitality Hunter becomes monstrous, put a lifelink counter on each of up to X target creatures.

Dominate

Gain control of target creature with mana value X or less.

Chromatic Armor

Enchant creature
As Chromatic Armor enters, choose a color.
Chromatic Armor enters with a sleight counter on it.
Prevent all damage that would be dealt to enchanted creature by sources of the last chosen color.
{X}: Put a sleight counter on Chromatic Armor and choose a color. X is the number of sleight counters on Chromatic Armor.

Logic Knot

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Counter target spell unless its controller pays {X}.

Path of the Ghosthunter

Create X 1/1 white Spirit creature tokens with flying.
Will of the Planeswalkers — Starting with you, each player votes for planeswalk or chaos. If planeswalk gets more votes, planeswalk. If chaos gets more votes or the vote is tied, chaos ensues.

Plant Tadpoles

Tap X target creatures. They don't untap during their controllers' next untap steps. (Then exile this card. You may cast the creature later from exile.)

Illithid Harvester

Ceremorphosis — When Illithid Harvester enters, turn any number of target tapped nontoken creatures face down. They're 2/2 Horror creatures.

Illithid Harvester // Plant Tadpoles

Well of Lost Dreams

Whenever you gain life, you may pay {X}, where X is less than or equal to the amount of life you gained. If you do, draw X cards.

Quarantine Field

Quarantine Field enters with X isolation counters on it.
When Quarantine Field enters, for each isolation counter on it, exile up to one target nonland permanent an opponent controls until Quarantine Field leaves the battlefield.

Kayla's Reconstruction

Look at the top seven cards of your library. Put up to X artifact and/or creature cards with mana value 3 or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.

Mind Spring

Aladdin's Lamp

{X}, {T}: The next time you would draw a card this turn, instead look at the top X cards of your library, put all but one of them on the bottom of your library in a random order, then draw a card. X can't be 0.

Drown in Dreams

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Target player draws X cards.
• Target player mills twice X cards.

Martial Coup

Create X 1/1 white Soldier creature tokens. If X is 5 or more, destroy all other creatures.

Walking Ballista

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

Elementalist's Palette

Whenever you cast a spell with {X} in its mana cost, put two charge counters on Elementalist's Palette.
{T}: Add one mana of any color.
{T}: Add {C} for each charge counter on Elementalist's Palette. Spend this mana only on costs that contain {X}.

Mishra's Helix

Distorting Wake

Return X target nonland permanents to their owners' hands.

Sphinx's Revelation

Unexpectedly Absent

Put target nonland permanent into its owner's library just beneath the top X cards of that library.

Return to the Ranks

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Return X target creature cards with mana value 2 or less from your graveyard to the battlefield.

Secure the Wastes

Create X 1/1 white Warrior creature tokens.

Karn's Sylex

Karn's Sylex enters tapped.
Players can't pay life to cast spells or to activate abilities that aren't mana abilities.
{X}, {T}, Exile Karn's Sylex: Destroy each nonland permanent with mana value X or less. Activate only as a sorcery.

Entreat the Angels

Create X 4/4 white Angel creature tokens with flying.
Miracle {X}{W}{W} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

Soul Foundry

Imprint — When Soul Foundry enters, you may exile a creature card from your hand.
{X}, {T}: Create a token that's a copy of the exiled card. X is the mana value of that card.

Ingenious Prodigy

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

Braingeyser

Sigil of Distinction

Sigil of Distinction enters with X charge counters on it.
Equipped creature gets +1/+1 for each charge counter on Sigil of Distinction.
Equip—Remove a charge counter from Sigil of Distinction.

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.

Pin Collection

When Pin Collection enters, you may put an ability sticker with ticket cost X or less on it without paying that sticker's ticket cost.
Equipped creature gets +1/+1 and has all abilities of ability stickers on Pin Collection.
Equip {2}

Gridlock

Thieving Skydiver

Kicker {X}. X can't be 0. (You may pay an additional {X} as you cast this spell.)
Flying
When Thieving Skydiver enters, if it was kicked, gain control of target artifact with mana value X or less. If that artifact is an Equipment, attach it to Thieving Skydiver.

Briber's Purse

Briber's Purse enters with X gem counters on it.
{1}, {T}, Remove a gem counter from Briber's Purse: Target creature can't attack or block this turn.

Omarthis, Ghostfire Initiate

Omarthis, Ghostfire Initiate enters with X +1/+1 counters on it.
Whenever you put one or more +1/+1 counters on another colorless creature, you may put a +1/+1 counter on Omarthis.
When Omarthis dies, manifest a number of cards from the top of your library equal to the number of counters on it.

Volcanic Eruption

Destroy X target Mountains. Volcanic Eruption deals damage to each creature and each player equal to the number of Mountains put into a graveyard this way.

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.

Temper

Prevent the next X damage that would be dealt to target creature this turn. For each 1 damage prevented this way, put a +1/+1 counter on that creature.

Prismatic Boon

Choose a color. X target creatures gain protection from the chosen color until end of turn.

Talon of Pain

Whenever a source you control other than Talon of Pain deals damage to an opponent, put a charge counter on Talon of Pain.
{X}, {T}, Remove X charge counters from Talon of Pain: It deals X damage to any target.

Skyscribing

Each player draws X cards.
Forecast — {2}{U}, Reveal Skyscribing from your hand: Each player draws a card. (Activate only during your upkeep and only once each turn.)

The Mana Rig

Whenever you cast a multicolored spell, create a tapped Powerstone token. (It's an artifact with "{T}: Add {C}. This mana can't be spent to cast a nonartifact spell.")
{X}{X}{X}, {T}: Look at the top X cards of your library. Put up to two of them into your hand and the rest on the bottom of your library in a random order.

Floodwater Dam

Repeal

Return target nonland permanent with mana value X to its owner's hand.
Draw a card.

Clockwork Swarm

Clockwork Swarm enters with four +1/+0 counters on it.
Clockwork Swarm can't be blocked by Walls.
At end of combat, if Clockwork Swarm attacked or blocked this combat, remove a +1/+0 counter from it.
{X}, {T}: Put up to X +1/+0 counters on Clockwork Swarm. This ability can't cause the total number of +1/+0 counters on Clockwork Swarm to be greater than four. Activate only during your upkeep.

Ugin's Conjurant

Ugin's Conjurant enters with X +1/+1 counters on it.
If damage would be dealt to Ugin's Conjurant while it has a +1/+1 counter on it, prevent that damage and remove that many +1/+1 counters from Ugin's Conjurant.

Cryptic Trilobite

Cryptic Trilobite enters with X +1/+1 counters on it.
Remove a +1/+1 counter from Cryptic Trilobite: Add {C}{C}. Spend this mana only to activate abilities.
{1}, {T}: Put a +1/+1 counter on Cryptic Trilobite.

Blue Sun's Twilight

Gain control of target creature with mana value X or less. If X is 5 or more, create a token that's a copy of that creature.

Grand Crescendo

Create X 1/1 green and white Citizen creature tokens. Creatures you control gain indestructible until end of turn.

Chalice of the Void

Chalice of the Void enters with X charge counters on it.
Whenever a player casts a spell with mana value equal to the number of charge counters on Chalice of the Void, counter that spell.

Breakthrough

Draw four cards, then choose X cards in your hand and discard the rest.

Metathran Aerostat

Flying
{X}{U}: You may put a creature card with mana value X from your hand onto the battlefield. If you do, return Metathran Aerostat to its owner's hand.

Mass Manipulation

Gain control of X target creatures and/or planeswalkers.

Prototype Portal

Imprint — When Prototype Portal enters, you may exile an artifact card from your hand.
{X}, {T}: Create a token that's a copy of the exiled card. X is the mana value of that card.

Ventifact Bottle

{X}{1}, {T}: Put X charge counters on Ventifact Bottle. Activate only as a sorcery.
At the beginning of your first main phase, if Ventifact Bottle has a charge counter on it, tap it and remove all charge counters from it. Add {C} for each charge counter removed this way.

Mirror Entity

Changeling (This card is every creature type.)
{X}: Until end of turn, creatures you control have base power and toughness X/X and gain all creature types.

Heroes' Podium

Each legendary creature you control gets +1/+1 for each other legendary creature you control.
{X}, {T}: Look at the top X cards of your library. You may reveal a legendary creature card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Part Water

X target creatures gain islandwalk until end of turn. (They can't be blocked as long as defending player controls an Island.)

Thassa's Intervention

Choose one —
• Look at the top X cards of your library. Put up to two of them into your hand and the rest on the bottom of your library in a random order.
• Counter target spell unless its controller pays twice {X}.