Black Sun's Zenith

Put X -1/-1 counters on each creature. Shuffle Black Sun's Zenith into its owner's library.

Mind Spring

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.

Displacement Wave

Return all nonland permanents with mana value X or less to their owners' hands.

Growth Spiral

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

Molder

Destroy target artifact or enchantment with mana value X. It can't be regenerated. You gain X life.

Iceberg

This enchantment enters with X ice counters on it.
{3}: Put an ice counter on this enchantment.
Remove an ice counter from this enchantment: Add {C}.

Erebos's Intervention

Choose one —
• Target creature gets -X/-X until end of turn. You gain X life.
• Exile up to twice X target cards from graveyards.

Nimbus Swimmer

Flying
This creature enters with X +1/+1 counters on it.

Squall Line

Squall Line deals X damage to each creature with flying and each player.

Pull from Tomorrow

Simic Signet

Swallowing Plague

Swallowing Plague deals X damage to target creature and you gain X life.

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.

Biomass Mutation

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

Chimeric Mass

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

Stonecoil Serpent

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

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.

Forest

Distorting Wake

Return X target nonland permanents to their owners' hands.

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.

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}.

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.

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.)

Reality Spasm

Choose one —
• Tap X target permanents.
• Untap X target permanents.

Mind Grind

Each opponent reveals cards from the top of their library until they reveal X land cards, then puts all cards revealed this way into their graveyard. X can't be 0.

Island

Maga, Traitor to Mortals

Maga enters with X +1/+1 counters on it.
When Maga enters, target player loses life equal to the number of +1/+1 counters on it.

Entrancing Melody

Gain control of target creature with mana value X.

Dimir Signet

Enshrined Memories

Reveal the top X cards of your library. Put all creature cards revealed this way into your hand and the rest on the bottom of your library in any order.

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.

Battle at the Bridge

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Target creature gets -X/-X until end of turn. You gain X life.

Llanowar Elves

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.

Profane Command

Choose two —
• Target player loses X life.
• Return target creature card with mana value X or less from your graveyard to the battlefield.
• Target creature gets -X/-X until end of turn.
• Up to X target creatures gain fear until end of turn. (They can't be blocked except by artifact creatures and/or black creatures.)

Torment of Hailfire

Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent of their choice or discards a card.

Cryptic Trilobite

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

Gadwick, the Wizened

When Gadwick enters, draw X cards.
Whenever you cast a blue spell, tap target nonland permanent an opponent controls.

Braingeyser

Swamp

Capricopian

This creature enters with X +1/+1 counters on it.
{2}: Put a +1/+1 counter on this creature, then you may reselect which player this creature is attacking. Only the player this creature is attacking may activate this ability and only during the declare attackers step. (It can't attack its controller.)

Death Cloud

Each player loses X life, discards X cards, sacrifices X creatures of their choice, then sacrifices X lands of their choice.

Golgari Signet

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.

Wurmcalling

Buyback {2}{G} (You may pay an additional {2}{G} as you cast this spell. If you do, put this card into your hand as it resolves.)
Create an X/X green Wurm creature token.

Selective Snare

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

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.

Epiphany at the Drownyard

Reveal the top X plus one cards of your library and separate them into two piles. An opponent chooses one of those piles. Put that pile into your hand and the other into your graveyard.

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

Deepglow Skate

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

Stream of Life

Vorel of the Hull Clade

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

Blue Sun's Zenith

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

Abandon Hope

As an additional cost to cast this spell, discard X cards.
Look at target opponent's hand and choose X cards from it. That player discards those cards.

Consume Spirit

Spend only black mana on X.
Consume Spirit deals X damage to any target and you gain X life.

Dregs of Sorrow

Destroy X target nonblack creatures. Draw X cards.

Kamahl's Druidic Vow

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Look at the top X cards of your library. You may put any number of land and/or legendary permanent cards with mana value X or less from among them onto the battlefield. Put the rest into your graveyard.

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.

Dominate

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

Killing Wave

For each creature, its controller sacrifices it unless they pay X life.

Serene Sunset

Prevent all combat damage X target creatures would deal this turn.

Hazardous Conditions

Creatures with no counters on them get -2/-2 until end of turn.

Zaxara, the Exemplary

Deathtouch
{T}: Add two mana of any one color.
Whenever you cast a spell with {X} in its mana cost, create a 0/0 green Hydra creature token, then put X +1/+1 counters on it.

Haunted Cloak

Equipped creature has vigilance, trample, and haste.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Stolen by the Fae

Return target creature with mana value X to its owner's hand. You create X 1/1 blue Faerie creature tokens with flying.

Nylea's Intervention

Choose one —
• Search your library for up to X land cards, reveal them, put them into your hand, then shuffle.
• Nylea's Intervention deals twice X damage to each creature with flying.

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.

Genesis Wave

Reveal the top X cards of your library. You may put any number of permanent cards with mana value X or less from among them onto the battlefield. Then put all cards revealed this way that weren't put onto the battlefield into your graveyard.

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.

Elvish Mystic

Gelatinous Genesis

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.)

Diabolic Revelation

Search your library for up to X cards, put those cards into your hand, then shuffle.

Villainous Wealth

Target opponent exiles the top X cards of their library. You may cast any number of spells with mana value X or less from among them without paying their mana costs.

Chalice of the Void

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

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."

Bond of Agony

As an additional cost to cast this spell, pay X life.
Each other player loses X life.

Briber's Purse

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

Psychic Drain

Target player mills X cards and you gain X life.

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}.

Herald of Secret Streams

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

Killing Glare

Destroy target creature with power X or less.

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.

Disembowel

Destroy target creature with mana value X.

Word of Binding

Curse of the Swine

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

Spell Burst

Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)
Counter target spell with mana value X.

Shapers of Nature

{3}{G}: Put a +1/+1 counter on target creature.
{2}{U}, Remove a +1/+1 counter from a creature you control: Draw a card.

Uncage the Menagerie

Search your library for up to X creature cards with different names that each have mana value X, reveal them, put them into your hand, then shuffle.

Corpsejack Menace

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

Nourishing Shoal

You may exile a green card with mana value X from your hand rather than pay this spell's mana cost.
You gain X life.

Gaze of Granite

Destroy each nonland permanent with mana value X or less.

Freed from the Real

Enchant creature
{U}: Tap enchanted creature.
{U}: Untap enchanted creature.

Damnable Pact

Target player draws X cards and loses X life.

Wildest Dreams

Return X target cards from your graveyard to your hand. Exile Wildest Dreams.

Stroke of Genius

Mass Manipulation

Gain control of X target creatures and/or planeswalkers.

Death Denied

Return X target creature cards from your graveyard to your hand.

Mind

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Draw two cards.

Spring

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