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.

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

Target creature gets +X/+X until end of turn, where X is your devotion to green. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)

Astral Cornucopia enters the battlefield with X charge counters on it.

{T}: Choose a color. Add one mana of that color for each charge counter on Astral Cornucopia.

Distribute three +1/+1 counters among one, two, or three target creatures, then double the number of +1/+1 counters on each of those creatures.

Castle Garenbrig enters the battlefield 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.

Lands you control have "{T}: Add one mana of any color."

{T}: Add one mana of any color.

You may spend mana as though it were mana of any color.

{T}: Add {C}{C}{C}{C}{C}.

{5}, {T}: Draw a card for each color among permanents you control.

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

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.

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.

Return target nonland permanent you don't control to its owner's hand.

Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

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.

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

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

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

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Feral Hydra enters with X +1/+1 counters on it.

{3}: Put a +1/+1 counter on Feral Hydra. Any player may activate this ability.

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

({T}: Add {G}.)

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.

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.

Grakmaw, Skyclave Ravager enters the battlefield with three +1/+1 counters on it.

Whenever another creature you control dies, if it had a +1/+1 counter on it, put a +1/+1 counter on Grakmaw.

When Grakmaw dies, create an X/X black and green Hydra creature token, where X is the number of +1/+1 counters on Grakmaw.

Gyrus, Waker of Corpses enters the battlefield with a number of +1/+1 counters on it equal to the amount of mana spent to cast it.

Whenever Gyrus attacks, you may exile target creature card with lesser power from your graveyard. If you do, create a token that's a copy of that card and that's tapped and attacking. Exile the token at end of combat.

If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.

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

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.

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.)

{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.

Whenever Hydra Omnivore deals combat damage to an opponent, it deals that much damage to each other opponent.

When you cast this spell, you gain half X life and draw half X cards. Round down each time.

Flying, trample

Hydroid Krasis enters the battlefield with X +1/+1 counters on it.

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

({T}: Add {U}.)

({T}: Add {U}.)

Jungle Hollow enters tapped.

When Jungle Hollow enters, you gain 1 life.

{T}: Add {B} or {G}.

Trample

Kalonian Hydra enters with four +1/+1 counters on it.

Whenever Kalonian Hydra attacks, double the number of +1/+1 counters on each creature you control.

{T}: Add {C}.

{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

This spell costs {G} less to cast for each green creature you control.

Trample

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.

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.

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

Trample

Whenever a player casts a spell, put a +1/+1 counter on Managorger Hydra.

At the beginning of your upkeep, put a +1/+1 counter on each creature you control if you control a creature with power 5 or greater. Then you gain 10 life if you control a creature with power 10 or greater. Then you win the game if you control a creature with power 20 or greater.

This spell can't be countered.

Haste, protection from blue

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

Monstrous Onslaught deals X damage divided as you choose among any number of target creatures, where X is the greatest power among creatures you control as you cast this spell.

Changeling (This card is every creature type.)

As Morophon, the Boundless enters the battlefield, choose a creature type.

Spells of the chosen type you cast cost {W}{U}{B}{R}{G} less to cast. This effect reduces only the amount of colored mana you pay.

Other creatures you control of the chosen type get +1/+1.

Destroy target creature or enchantment.

({T}: Add {R}.)

({T}: Add {R}.)

Trample

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

Trample

Landfall -- Whenever a land enters the battlefield under your control, put a +1/+1 counter on Oran-Rief Hydra. If that land is a Forest, put two +1/+1 counters on Oran-Rief Hydra instead.

Path of Ancestry enters tapped.

{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

If damage would be dealt to Phytohydra, put that many +1/+1 counters on it instead.

({T}: Add {W}.)

({T}: Add {W}.)

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.

Protection from everything

If Progenitus would be put into a graveyard from anywhere, reveal Progenitus and shuffle it into its owner's library instead.

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.

You have no maximum hand size.

{T}: Add {C}.

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.)

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

Rugged Highlands enters the battlefield tapped.

When Rugged Highlands enters the battlefield, you gain 1 life.

{T}: Add {R} or {G}.

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.

{T}: Add {C}{C}.

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

{2}{G}, Remove a +1/+1 counter from Steelbane Hydra: Destroy target artifact or enchantment.

({T}: Add {B}.)

({T}: Add {B}.)

{T}: Add {C}{C}. Activate only if you control five or more lands.

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

This spell costs {X} less to cast, where X is the greatest power among creatures you control.

{T}: Add {G}{G}. You gain 2 life.

Whenever a nontoken creature enters the battlefield under your control, put a +1/+1 counter on it and draw a card.

{T}: Add {C}{C}{C}.

Reach

Ulvenwald Hydra's power and toughness are each equal to the number of lands you control.

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

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.

As Unclaimed Territory enters the battlefield, choose a creature type.

{T}: Add {C}.

{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

As Vanquisher's Banner enters the battlefield, choose a creature type.

Creatures you control of the chosen type get +1/+1.

Whenever you cast a creature spell of the chosen type, draw a card.

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.

Trample

If damage would be dealt to another creature you control, prevent that damage. Put a +1/+1 counter on that creature for each 1 damage prevented this way.

When Vigor is put into a graveyard from anywhere, shuffle it into its owner's library.

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.

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.

Trample, haste

If you would put one or more counters on a permanent or player, put twice that many of each of those kinds of counters on that permanent or player instead.

If an opponent would put one or more counters on a permanent or player, they put half that many of each of those kinds of counters on that permanent or player instead, rounded down.

Reach

When Whiptongue Hydra enters the battlefield, destroy all creatures with flying. Put a +1/+1 counter on Whiptongue Hydra for each creature destroyed this way.

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.