Voracious Hydra

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

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.
Genesis Hydra enters the battlefield with X +1/+1 counters on it.

Up the Beanstalk

When Up the Beanstalk enters the battlefield and whenever you cast a spell with mana value 5 or greater, draw a card.

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.)

Rockfall Vale

Rockfall Vale enters the battlefield tapped unless you control two or more other lands.
{T}: Add {R} or {G}.

Rootbound Crag

Rootbound Crag enters the battlefield tapped unless you control a Mountain or a Forest.
{T}: Add {R} or {G}.

Gruul Turf

Gruul Turf enters the battlefield tapped.
When Gruul Turf enters the battlefield, return a land you control to its owner's hand.
{T}: Add {R}{G}.

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.

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.

Lumra, Bellow of the Woods

Vigilance, reach
Lumra, Bellow of the Woods's power and toughness are each equal to the number of lands you control.
When Lumra enters, mill four cards. Then return all land cards from your graveyard to the battlefield tapped.

Warstorm Surge

Whenever a creature enters the battlefield under your control, it deals damage equal to its power to any target.

Beast Within

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

Hooded Hydra

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

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.)

Worldsoul's Rage

Worldsoul's Rage deals X damage to any target. Put up to X land cards from your hand and/or graveyard onto the battlefield tapped.

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}.

All Will Be One

Whenever you put one or more counters on a permanent or player, All Will Be One deals that much damage to target opponent, creature an opponent controls, or planeswalker an opponent controls.

Zendikar Resurgent

Whenever you tap a land for mana, add one mana of any type that land produced. (The types of mana are white, blue, black, red, green, and colorless.)
Whenever you cast a creature spell, draw a card.

Selvala, Heart of the Wilds

Whenever another creature enters the battlefield, its controller may draw a card if its power is greater than each other creature's power.
{G}, {T}: Add X mana in any combination of colors, where X is the greatest power among creatures you control.

Sol Ring

Colossal Majesty

At the beginning of your upkeep, if you control a creature with power 4 or greater, draw a card.

Skarrg, the Rage Pits

{T}: Add {C}.
{R}{G}, {T}: Target creature gets +1/+1 and gains trample until end of turn.

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.

Crackle with Power

Crackle with Power deals five times X damage to each of up to X targets.

Ochre Jelly

Trample
Ochre Jelly enters the battlefield with X +1/+1 counters on it.
Split — When Ochre Jelly dies, if it had two or more +1/+1 counters on it, create a token that's a copy of it at the beginning of the next end step. The token enters the battlefield with half that many +1/+1 counters on it, rounded down.

Goblin Anarchomancer

Each spell you cast that's red or green costs {1} less to cast.

Lair of the Hydra

If you control two or more other lands, Lair of the Hydra enters the battlefield tapped.
{T}: Add {G}.
{X}{G}: Until end of turn, Lair of the Hydra becomes an X/X green Hydra creature. It's still a land. X can't be 0.

Lifeblood Hydra

Trample
Lifeblood Hydra enters the battlefield with X +1/+1 counters on it.
When Lifeblood Hydra dies, you gain life and draw cards equal to its power.

Mistcutter Hydra

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

Gruul Signet

Rosheen Meanderer

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

Cinder Glade

({T}: Add {R} or {G}.)
Cinder Glade enters the battlefield tapped unless you control two or more basic lands.

Rishkar's Expertise

Draw cards equal to the greatest power among creatures you control.
You may cast a spell with mana value 5 or less from your hand without paying its mana cost.

Mana Reflection

If you tap a permanent for mana, it produces twice as much of that mana instead.

Neverwinter Hydra

As Neverwinter Hydra enters the battlefield, roll X d6. It enters with a number of +1/+1 counters on it equal to the total of those results.
Trample
Ward {4} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {4}.)

Awaken the Woods

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

Primordial Hydra

Primordial Hydra enters the battlefield with X +1/+1 counters on it.
At the beginning of your upkeep, double the number of +1/+1 counters on Primordial Hydra.
Primordial Hydra has trample as long as it has ten or more +1/+1 counters on it.

Stonecoil Serpent

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

Savageborn Hydra

Double strike
Savageborn Hydra enters the battlefield with X +1/+1 counters on it.
{1}{R/G}: Put a +1/+1 counter on Savageborn Hydra. Activate only as a sorcery.

Llanowar Elves

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.

Reliquary Tower

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

Klauth's Will

Choose one. If you control a commander as you cast this spell, you may choose both.
• Breathe Flame — Klauth's Will deals X damage to each creature without flying.
• Smash Relics — Destroy up to X target artifacts and/or enchantments.

Sporocyst

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

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.

Kessig Wolf Run

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

Delete

Delete deals X damage to each nonartifact creature and each player.

Harmonize

Apocalypse Hydra

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

Temple of Abandon

Temple of Abandon enters the battlefield tapped.
When Temple of Abandon enters the battlefield, scry 1.
{T}: Add {R} or {G}.

Rhythm of the Wild

Creature spells you control can't be countered.
Nontoken creatures you control have riot. (They enter the battlefield with your choice of a +1/+1 counter or haste.)

Mountain

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Decimate

Destroy target artifact, target creature, target enchantment, and target land. (You can't cast this spell unless you have legal choices for all its targets.)

Arcane Signet

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

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Return of the Wildspeaker

Choose one —
• Draw cards equal to the greatest power among non-Human creatures you control.
• Non-Human creatures you control get +3/+3 until end of turn.

Rampant Growth

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

Elvish Mystic

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.

Gelatinous Genesis

Forest

Game Trail

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

Lightning Greaves

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

Garruk's Uprising

When Garruk's Uprising enters the battlefield, if you control a creature with power 4 or greater, draw a card.
Creatures you control have trample. (They can deal excess combat damage to the player or planeswalker they're attacking.)
Whenever a creature with power 4 or greater enters the battlefield under your control, draw a card.

Rogue's Passage

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

Nexos

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

Shivan Devastator

Flying, haste
Shivan Devastator enters the battlefield with X +1/+1 counters on it.

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.

Command Tower

Rampaging Yao Guai

Vigilance, trample
Rampaging Yao Guai enters the battlefield with X +1/+1 counters on it.
When Rampaging Yao Guai enters the battlefield, destroy any number of target artifacts and/or enchantments with total mana value X or less.

Mawloc

Ravenous (This creature enters the battlefield with X +1/+1 counters on it. If X is 5 or more, draw a card when it enters.)
Terror from the Deep — When Mawloc enters the battlefield, it fights up to one target creature an opponent controls. If that creature would die this turn, exile it instead.

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.

Gargos, Vicious Watcher

Vigilance
Hydra spells you cast cost {4} less to cast.
Whenever a creature you control becomes the target of a spell, Gargos, Vicious Watcher fights up to one target creature you don't control.

Goldvein Hydra

Vigilance, trample, haste
Goldvein Hydra enters the battlefield with X +1/+1 counters on it.
When Goldvein Hydra dies, create a number of tapped Treasure tokens equal to its power.

Vastwood Hydra

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

Spiteful Banditry

When Spiteful Banditry enters the battlefield, it deals X damage to each creature.
Whenever one or more creatures your opponents control die, you create a Treasure token. This ability triggers only once each turn.

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.

Reap the Past

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

Protean Hydra

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