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.

Rootbound Crag

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

Harmonize

Forest

Wilderness Reclamation

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

Thran Dynamo

Red Sun's Zenith

Red Sun's Zenith deals X damage to any target. If a creature dealt damage this way would die this turn, exile it instead. Shuffle Red Sun's Zenith into its owner's library.

Feral Hydra

This creature enters with X +1/+1 counters on it.
{3}: Put a +1/+1 counter on this creature. Any player may activate this ability.

Rancor

Enchant creature
Enchanted creature gets +2/+0 and has trample.
When this Aura is put into a graveyard from the battlefield, return it to its owner's hand.

Cinder Glade

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

Arashi, the Sky Asunder

{X}{G}, {T}: Arashi deals X damage to target creature with flying.
Channel — {X}{G}{G}, Discard this card: It deals X damage to each creature with flying.

Savageborn Hydra

Double strike
This creature enters with X +1/+1 counters on it.
{1}{R/G}: Put a +1/+1 counter on this creature. Activate only as a sorcery.

Chandra, Torch of Defiance

+1: Exile the top card of your library. You may cast that card. If you don't, Chandra deals 2 damage to each opponent.
+1: Add {R}{R}.
−3: Chandra deals 4 damage to target creature.
−7: You get an emblem with "Whenever you cast a spell, this emblem deals 5 damage to any target."

Starstorm

Starstorm deals X damage to each creature.
Cycling {3} ({3}, Discard this card: Draw a card.)

Mountain

Wooded Foothills

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

Purphoros's Intervention

Choose one —
• Create an X/1 red Elemental creature token with trample and haste. Sacrifice it at the beginning of the next end step.
• Purphoros's Intervention deals twice X damage to target creature or planeswalker.

Bonfire of the Damned

Bonfire of the Damned deals X damage to target player or planeswalker and each creature that player or that planeswalker's controller controls.
Miracle {X}{R} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

Command Tower

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

Comet Storm

Multikicker {1} (You may pay an additional {1} any number of times as you cast this spell.)
Choose any target, then choose another target for each time this spell was kicked. Comet Storm deals X damage to each of them.

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.

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.

Burn from Within

Burn from Within deals X damage to any target. If a creature is dealt damage this way, it loses indestructible until end of turn. If that creature would die this turn, exile it instead.

Release the Gremlins

Destroy X target artifacts. Create X 2/2 red Gremlin creature tokens.

Molten Disaster

Kicker {R} (You may pay an additional {R} as you cast this spell.)
If this spell was kicked, it has split second. (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Molten Disaster deals X damage to each creature without flying and each player.

Clan Defiance

Choose one or more —
• Clan Defiance deals X damage to target creature with flying.
• Clan Defiance deals X damage to target creature without flying.
• Clan Defiance deals X damage to target player or planeswalker.

Game Trail

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

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.

Jaya's Immolating Inferno

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Jaya's Immolating Inferno deals X damage to each of up to three targets.

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.

Silklash Spider

Reach
{X}{G}{G}: This creature deals X damage to each creature with flying.

Banefire

Banefire deals X damage to any target.
If X is 5 or more, this spell can't be countered and the damage can't be prevented.

Fall of the Titans

Surge {X}{R} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Fall of the Titans deals X damage to each of up to two targets.

Blaze

Rosheen Meanderer

{T}: Add {C}{C}{C}{C}. Spend this mana only on costs that contain {X}.

Finale of Devastation

Search your library and/or graveyard for a creature card with mana value X or less and put it onto the battlefield. If you search your library this way, shuffle. If X is 10 or more, creatures you control get +X/+X and gain haste until end of turn.

Mistcutter Hydra

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

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.

Polukranos, World Eater

{X}{X}{G}: Monstrosity X. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)
When Polukranos becomes monstrous, it deals X damage divided as you choose among any number of target creatures your opponents control. Each of those creatures deals damage equal to its power to Polukranos.

Reap the Past

Return X cards at random from your graveyard to your hand. Exile Reap the Past.

Shifting Wall

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

Rolling Thunder

Rolling Thunder deals X damage divided as you choose among any number of targets.

Electrodominance

Electrodominance deals X damage to any target. You may cast a spell with mana value X or less from your hand without paying its mana cost.

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.

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.

Hydra Broodmaster

{X}{X}{G}: Monstrosity X. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)
When this creature becomes monstrous, create X X/X green Hydra creature tokens.

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.

Earthquake

Earthquake deals X damage to each creature without flying and each player.

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.

Sol Ring

Demonfire

Demonfire deals X damage to any target. If a creature dealt damage this way would die this turn, exile it instead.
Hellbent — If you have no cards in hand, this spell can't be countered and the damage can't be prevented.

Rogue's Passage

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

Kodama's Reach

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.

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."

Grove of the Burnwillows

{T}: Add {C}.
{T}: Add {R} or {G}. Each opponent gains 1 life.

Staff of Nin

At the beginning of your upkeep, draw a card.
{T}: This artifact deals 1 damage to any target.

Kessig Wolf Run

{T}: Add {C}.
{X}{R}{G}, {T}: Target creature gets +X/+0 and gains trample until end of turn.

Steel Hellkite

Flying
{2}: This creature gets +1/+0 until end of turn.
{X}: Destroy each nonland permanent with mana value X whose controller was dealt combat damage by this creature this turn. Activate only once each turn.

Fireball

This spell costs {1} more to cast for each target beyond the first.
Fireball deals X damage divided evenly, rounded down, among any number of targets.

Nylea, God of the Hunt

Indestructible
As long as your devotion to green is less than five, Nylea isn't a creature. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)
Other creatures you control have trample.
{3}{G}: Target creature gets +2/+2 until end of turn.

Apocalypse Hydra

This creature enters with X +1/+1 counters on it. If X is 5 or more, it enters with an additional X +1/+1 counters on it.
{1}{R}, Remove a +1/+1 counter from this creature: It deals 1 damage to any target.

Stonecoil Serpent

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

Hooded Hydra

This creature enters with X +1/+1 counters on it.
When this creature dies, create a 1/1 green Snake creature token for each +1/+1 counter on it.
Morph {3}{G}{G}
As this creature is turned face up, put five +1/+1 counters on it.

Raging Ravine

This land enters tapped.
{T}: Add {R} or {G}.
{2}{R}{G}: Until end of turn, this land becomes a 3/3 red and green Elemental creature with "Whenever this creature attacks, put a +1/+1 counter on it." It's still a land.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Wildest Dreams

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

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.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Temple of Abandon

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

Ivy Elemental

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

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.

Cultivate

Crater's Claws

Crater's Claws deals X damage to any target.
Ferocious — Crater's Claws deals X plus 2 damage instead if you control a creature with power 4 or greater.

Endless One

Gelatinous Genesis

Devil's Play

Devil's Play deals X damage to any target.
Flashback {X}{R}{R}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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.)