Mistcutter Hydra

This spell can't be countered.
Haste, protection from blue
This creature enters with X +1/+1 counters on it.

Gyre Sage

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
{T}: Add {G} for each +1/+1 counter on this creature.

Sporocyst

Ravenous (This creature enters with X +1/+1 counters on it. If X is 5 or more, draw a card when it enters.)
Defender
Spore Chimney — When this creature enters, search your library for up to X basic land cards, put them onto the battlefield tapped, 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.

Island

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.

Seedborn Muse

Untap all permanents you control during each other player's untap step.

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.

Command Tower

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

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.

Hinterland Harbor

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

Arcane Signet

Misty Rainforest

{T}, Pay 1 life, Sacrifice this land: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

Aberrant

Ravenous (This creature enters with X +1/+1 counters on it. If X is 5 or more, draw a card when it enters.)
Trample
Heavy Power Hammer — Whenever this creature deals combat damage to a player, destroy target artifact or enchantment that player controls.

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}.

Sol Ring

Tidechannel Pathway

Barkchannel Pathway

Barkchannel Pathway // Tidechannel Pathway

Curse of the Swine

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

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

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.

Llanowar Wastes

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

Overgrown Tomb

({T}: Add {B} or {G}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Awaken the Woods

Create X 1/1 green Forest Dryad land creature tokens. (They're affected by summoning sickness.)

Death Denied

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

Forest

Shipwreck Marsh

This land enters tapped unless you control two or more other lands.
{T}: Add {U} or {B}.

Dreamroot Cascade

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

Slitherbore Pathway

Darkbore Pathway

Darkbore Pathway // Slitherbore Pathway

Morphic Pool

This land enters tapped unless you have two or more opponents.
{T}: Add {U} or {B}.

Genesis Hydra

When you cast this spell, reveal the top X cards of your library. You may put a nonland permanent card with mana value X or less from among them onto the battlefield. Then shuffle the rest into your library.
This creature enters with X +1/+1 counters on it.

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.

Blue Sun's Zenith

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

Deathcap Glade

This land enters tapped unless you control two or more other lands.
{T}: Add {B} or {G}.

Vastwood Hydra

This creature enters with X +1/+1 counters on it.
When this creature dies, you may distribute a number of +1/+1 counters equal to the number of +1/+1 counters on this creature among any number of creatures you control.

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.

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.)

Nexos

Strategic Coordinator — Basic lands you control have "{T}: Add {C}{C}. Spend this mana only on costs that contain {X}."

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.

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}.

Herald of Secret Streams

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

Woodland Cemetery

This land enters tapped unless you control a Swamp or a Forest.
{T}: Add {B} or {G}.

Green Sun's Zenith

Search your library for a green creature card with mana value X or less, put it onto the battlefield, then shuffle. Shuffle Green Sun's Zenith into its owner's library.

Takenuma, Abandoned Mire

{T}: Add {B}.
Channel — {3}{B}, Discard this card: Mill three cards, then return a creature or planeswalker card from your graveyard to your hand. This ability costs {1} less to activate for each legendary creature you control.

Nature's Lore

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

Stonecoil Serpent

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

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.

Three Visits

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

Doubling Season

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

Yavimaya Coast

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

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.

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.

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.

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.

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.

Swamp

Drowned Catacomb

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

Breeding Pool

({T}: Add {G} or {U}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Inspiring Call

Draw a card for each creature you control with a +1/+1 counter on it. Those creatures gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

Exotic Orchard

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

Walking Ballista

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

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.)

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.

Reliquary Tower

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

Tyvar's Stand

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

Yavimaya, Cradle of Growth

Each land is a Forest in addition to its other land types.

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.

Undergrowth Stadium

This land enters tapped unless you have two or more opponents.
{T}: Add {B} or {G}.

Protean Hydra

This creature enters with X +1/+1 counters on it.
If damage would be dealt to this creature, prevent that damage and remove that many +1/+1 counters from it.
Whenever a +1/+1 counter is removed from this creature, put two +1/+1 counters on it at the beginning of the next end step.

Gadwick, the Wizened

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

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.

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.

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.

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.

Watery Grave

({T}: Add {U} or {B}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Verdant Catacombs

{T}, Pay 1 life, Sacrifice this land: Search your library for a Swamp or Forest card, put it onto the battlefield, then shuffle.

City of Brass

Whenever this land becomes tapped, it deals 1 damage to you.
{T}: Add one mana of any color.

Opulent Palace

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

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.

Runadi, Behemoth Caller

Whenever you cast a creature spell with mana value 5 or greater, that creature enters with X additional +1/+1 counters on it, where X is its mana value minus 4.
Creatures you control with three or more +1/+1 counters on them have haste.
{T}: Add {G}.

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.

Wilderness Reclamation

At the beginning of your end step, untap all lands you control.

Rejuvenating Springs

This land enters tapped unless you have two or more opponents.
{T}: Add {G} or {U}.

Black Sun's Zenith

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

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.)

Gaze of Granite

Destroy each nonland permanent with mana value X or less.

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.

Castle Garenbrig

This land enters tapped unless you control a Forest.
{T}: Add {G}.
{2}{G}{G}, {T}: Add six {G}. Spend this mana only to cast creature spells or activate abilities of creatures.

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Beast Within

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

Zagoth Triome

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

Pull from Tomorrow

Voracious Hydra

Trample
This creature enters with X +1/+1 counters on it.
When this creature enters, choose one —
• Double the number of +1/+1 counters on this creature.
• This creature fights target creature you don't control.

Exsanguinate

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

Hungering Hydra

This creature enters with X +1/+1 counters on it.
This creature can't be blocked by more than one creature.
Whenever this creature is dealt damage, put that many +1/+1 counters on it. (It must survive the damage to get the counters.)

Otawara, Soaring City

{T}: Add {U}.
Channel — {3}{U}, Discard this card: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

Green Sun's Twilight

Reveal the top X plus one cards of your library. Choose a creature card and/or a land card from among them. Put those cards into your hand and the rest on the bottom of your library in a random order. If X is 5 or more, instead put the chosen cards onto the battlefield or into your hand and the rest on the bottom of your library in a random order.