Rosheen Meanderer

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

Death's Presence

Whenever a creature you control dies, put X +1/+1 counters on target creature you control, where X is the power of the creature that died.

Soulbright Flamekin

{2}: Target creature gains trample until end of turn. If this is the third time this ability has resolved this turn, you may add {R}{R}{R}{R}{R}{R}{R}{R}.

Wren's Run Hydra

Reach
Wren's Run Hydra enters the battlefield with X +1/+1 counters on it.
Reinforce X—{X}{G}{G} ({X}{G}{G}, Discard this card: Put X +1/+1 counters on target creature.)

Wild Growth

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G}.

Horizon Stone

If you would lose unspent mana, that mana becomes colorless instead.

Domesticated Hydra

{X}{G}{G}{G}: Monstrosity X. (If this creature isn't monstrous, put X +1/+1 counters on it and it becomes monstrous.)
As long as Domesticated Hydra is monstrous, it has trample.

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.

Elvish Mystic

Savage Ventmaw

Flying
Whenever Savage Ventmaw attacks, add {R}{R}{R}{G}{G}{G}. Until end of turn, you don't lose this mana as steps and phases end.

Orochi Hatchery

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

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.

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.

Goblin Anarchomancer

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

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.

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}.

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.

Harrow

As an additional cost to cast this spell, sacrifice a land.
Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Heat Ray

Heat Ray deals X damage to target creature.

Strength of the Tajuru

Multikicker {1} (You may pay an additional {1} any number of times as you cast this spell.)
Choose target creature, then choose another target creature for each time this spell was kicked. Put X +1/+1 counters on each of them.

Wildwood Scourge

Wildwood Scourge enters the battlefield with X +1/+1 counters on it.
Whenever one or more +1/+1 counters are put on another non-Hydra creature you control, put a +1/+1 counter on Wildwood Scourge.

Farhaven Elf

When Farhaven Elf enters the battlefield, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Llanowar Elves

Hydra's Growth

Enchant creature
When Hydra's Growth enters the battlefield, put a +1/+1 counter on enchanted creature.
At the beginning of your upkeep, double the number of +1/+1 counters on enchanted creature.

Grand Warlord Radha

Haste
Whenever one or more creatures you control attack, add that much mana in any combination of {R} and/or {G}. Until end of turn, you don't lose this mana as steps and phases end.

Search for Tomorrow

Search your library for a basic land card, put it onto the battlefield, then shuffle.
Suspend 2—{G} (Rather than cast this card from your hand, you may pay {G} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Exponential Growth

Until end of turn, double target creature's power X times.

Rampant Growth

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

Mountain

Reclamation Sage

When Reclamation Sage enters the battlefield, you may destroy target artifact or enchantment.

Ivy Elemental

Ivy Elemental enters the battlefield with X +1/+1 counters on it.

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.

Hungering Hydra

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

Ironscale Hydra

If a creature would deal combat damage to Ironscale Hydra, prevent that damage and put a +1/+1 counter on Ironscale Hydra.

Mana Bloom

Mana Bloom enters the battlefield with X charge counters on it.
Remove a charge counter from Mana Bloom: Add one mana of any color. Activate only once each turn.
At the beginning of your upkeep, if Mana Bloom has no charge counters on it, return it to its owner's hand.

Warstorm Surge

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

Harmonize

Beast Whisperer

Whenever you cast a creature spell, draw a card.

Molder

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

Gruul Ragebeast

Whenever Gruul Ragebeast or another creature enters the battlefield under your control, that creature fights target creature an opponent controls.

Wave of Indifference

X target creatures can't block this turn.

Aggressive Mammoth

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Other creatures you control have trample.

Krakilin

Krakilin enters the battlefield with X +1/+1 counters on it.
{1}{G}: Regenerate Krakilin.

Rolling Thunder

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

Assault Formation

Each creature you control assigns combat damage equal to its toughness rather than its power.
{G}: Target creature with defender can attack this turn as though it didn't have defender.
{2}{G}: Creatures you control get +0/+1 until end of 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.

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Capricopian

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

Flameblast Dragon

Flying
Whenever Flameblast Dragon attacks, you may pay {X}{R}. If you do, Flameblast Dragon deals X damage to any target.

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.

Savage Twister

Savage Twister deals X damage to each creature.

Gruul Locket

{T}: Add {R} or {G}.
{R/G}{R/G}{R/G}{R/G}, {T}, Sacrifice Gruul Locket: Draw two cards.

Destructive Revelry

Destroy target artifact or enchantment. Destructive Revelry deals 2 damage to that permanent's controller.

Brawn

Trample
As long as Brawn is in your graveyard and you control a Forest, creatures you control have trample.

Reap the Past

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

Colossal Majesty

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

Fertile Ground

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional one mana of any color.

Fractal Harness

When Fractal Harness enters the battlefield, create a 0/0 green and blue Fractal creature token. Put X +1/+1 counters on it and attach Fractal Harness to it.
Whenever equipped creature attacks, double the number of +1/+1 counters on it.
Equip {2}

Heroes' Bane

Heroes' Bane enters the battlefield with four +1/+1 counters on it.
{2}{G}{G}: Put X +1/+1 counters on Heroes' Bane, where X is its power.

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 Hydra Broodmaster becomes monstrous, create X X/X green Hydra creature tokens.

Zhur-Taa Druid

{T}: Add {G}.
Whenever you tap Zhur-Taa Druid for mana, it deals 1 damage to each opponent.

Greater Good

Sacrifice a creature: Draw cards equal to the sacrificed creature's power, then discard three cards.

Khenra Charioteer

Trample
Other creatures you control have trample.

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.)

Signal the Clans

Search your library for three creature cards and reveal them. If you reveal three cards with different names, choose one of them at random and put that card into your hand. Shuffle the rest into your library.

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.

Wolfwillow Haven

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G}.
{4}{G}, Sacrifice Wolfwillow Haven: Create a 2/2 green Wolf creature token. Activate only during your turn.

Forest

Gruul Signet

Momentous Fall

As an additional cost to cast this spell, sacrifice a creature.
You draw cards equal to the sacrificed creature's power, then you gain life equal to its toughness.

Garruk's Packleader

Whenever another creature with power 3 or greater enters the battlefield under your control, you may draw a card.

Fires of Yavimaya

Creatures you control have haste.
Sacrifice Fires of Yavimaya: Target creature gets +2/+2 until end of turn.

Utopia Sprawl

Enchant Forest
As Utopia Sprawl enters the battlefield, choose a color.
Whenever enchanted Forest is tapped for mana, its controller adds an additional one mana of the chosen color.

Return to Nature

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Exile target card from a graveyard.