Iceberg

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

Stonecoil Serpent

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

Dominate

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

Grand Crescendo

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

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.

Abuelo's Awakening

Return target artifact or non-Aura enchantment card from your graveyard to the battlefield with X additional +1/+1 counters on it. It's a 1/1 Spirit creature with flying in addition to its other types.

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.

Orochi Hatchery

Orochi Hatchery enters with X charge counters on it.
{5}, {T}: Create a 1/1 green Snake creature token for each charge counter on Orochi Hatchery.

Kami of the Crescent Moon

At the beginning of each player's draw step, that player draws an additional card.

Hail of Arrows

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

Curse of the Swine

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

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.

White Sun's Zenith

Create X 2/2 white Cat creature tokens. Shuffle White Sun's Zenith into its owner's library.

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.

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.

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.

Mass Manipulation

Gain control of X target creatures and/or planeswalkers.

Zenith Chronicler

Whenever a player casts their first multicolored spell each turn, each other player draws a card.

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.

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.

Dictate of Kruphix

Flash (You may cast this spell any time you could cast an instant.)
At the beginning of each player's draw step, that player draws an additional card.

Otherworld Atlas

{T}: Put a charge counter on Otherworld Atlas.
{T}: Each player draws a card for each charge counter on Otherworld Atlas.

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.

Progenitor Exarch

When Progenitor Exarch enters, incubate 3 X times. (To incubate 3, create an Incubator token with three +1/+1 counters on it and "{2}: Transform this artifact." It transforms into a 0/0 Phyrexian artifact creature.)
{T}: Transform target Incubator token you control.

Festival of the Guildpact

Prevent the next X damage that would be dealt to you this turn.
Draw a card.

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.

Sphinx of the Second Sun

Flying
At the beginning of each of your postcombat main phases, there is an additional beginning phase after this phase. (The beginning phase includes the untap, upkeep, and draw steps.)

Anvil of Bogardan

Players have no maximum hand size.
At the beginning of each player's draw step, that player draws an additional card, then discards a card.

Walking Archive

Defender (This creature can't attack.)
Walking Archive enters with a +1/+1 counter on it.
At the beginning of each player's upkeep, that player draws a card for each +1/+1 counter on Walking Archive.
{2}{W}{U}: Put a +1/+1 counter on Walking Archive.

Heliod's Intervention

Choose one —
• Destroy X target artifacts and/or enchantments.
• Target player gains twice X life.

Decree of Justice

Create X 4/4 white Angel creature tokens with flying.
Cycling {2}{W} ({2}{W}, Discard this card: Draw a card.)
When you cycle Decree of Justice, you may pay {X}. If you do, create X 1/1 white Soldier creature tokens.

Heliod, the Warped Eclipse

You may cast spells as though they had flash.
Spells you cast cost {1} less to cast for each card your opponents have drawn this turn.

Heliod, the Radiant Dawn

When Heliod, the Radiant Dawn enters, return target enchantment card that isn't a God from your graveyard to your hand.
{3}{U/P}: Transform Heliod, the Radiant Dawn. Activate only as a sorcery. ({U/P} can be paid with either {U} or 2 life.)

Heliod, the Radiant Dawn // Heliod, the Warped Eclipse

Glimpse the Sun God

Tap X target creatures. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Gridlock

Teferi Akosa of Zhalfir

+1: Draw two cards. Then discard two cards unless you discard a creature card.
−2: You get an emblem with "Knights you control get +1/+0 and have ward {1}."
−3: Tap any number of untapped creatures you control. When you do, shuffle target nonland permanent an opponent controls with mana value X or less into its owner's library, where X is the number of creatures tapped this way.

Invasion of New Phyrexia

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of New Phyrexia enters, create X 2/2 white and blue Knight creature tokens with vigilance.

Invasion of New Phyrexia // Teferi Akosa of Zhalfir

Well of Ideas

When Well of Ideas enters, draw two cards.
At the beginning of each other player's draw step, that player draws an additional card.
At the beginning of your draw step, draw two additional cards.

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.

Temple Bell

Entrancing Melody

Gain control of target creature with mana value X.

Endless One

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

Prosperity

Excise

Exile target attacking creature unless its controller pays {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.)

Minds Aglow

Join forces — Starting with you, each player may pay any amount of mana. Each player draws X cards, where X is the total amount of mana paid this way.

Consecrated Sphinx

Flying
Whenever an opponent draws a card, you may draw two cards.

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.)

Font of Mythos

At the beginning of each player's draw step, that player draws two additional cards.

Faerie Mastermind

Flash
Flying
Whenever an opponent draws their second card each turn, you draw a card.
{3}{U}: Each player draws a card.

Lost in the Maze

Flash
When Lost in the Maze 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.

Broken Ambitions

Counter target spell unless its controller pays {X}. Clash with an opponent. If you win, that spell's controller mills four cards. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)

Shifting Wall

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

Awakened Awareness

Enchant artifact or creature
When Awakened Awareness enters, put X +1/+1 counters on enchanted permanent.
As long as enchanted permanent is a creature, it has base power and toughness 1/1.

Howling Mine

At the beginning of each player's draw step, if Howling Mine is untapped, that player draws an additional card.

Clash of Wills

Counter target spell unless its controller pays {X}.

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.

Howling Golem

Whenever Howling Golem attacks or blocks, each player draws a card.

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.

Fascination

Choose one —
• Each player draws X cards.
• Each player mills X cards.

Dance of the Manse

Return up to X target artifact and/or non-Aura enchantment cards each with mana value X or less from your graveyard to the battlefield. If X is 6 or more, those permanents are 4/4 creatures in addition to their other types.

Ertai's Meddling

X can't be 0.
Target spell's controller exiles it with X delay counters on it.
At the beginning of each of that player's upkeeps, if that card is exiled, remove a delay counter from it. If the card has no delay counters on it, the player puts it onto the stack as a copy of the original spell.