Have

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Arcane Signet

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

Hydra Omnivore

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

Swamp

Ulvenwald Hydra

Reach
Ulvenwald Hydra's power and toughness are each equal to the number of lands you control.
When Ulvenwald Hydra enters, you may search your library for a land card, put it onto the battlefield tapped, then shuffle.

Opulent Palace

Opulent Palace enters tapped.
{T}: Add {B}, {G}, or {U}.

Quest for Renewal

Whenever a creature you control becomes tapped, you may put a quest counter on Quest for Renewal.
As long as there are four or more quest counters on Quest for Renewal, untap all creatures you control during each other player's untap step.

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 with X +1/+1 counters on it.

Paradise Druid

This creature has hexproof as long as it's untapped. (It can't be the target of spells or abilities your opponents control.)
{T}: Add one mana of any color.

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.

Garruk's Uprising

When this enchantment enters, if you control a creature with power 4 or greater, draw a card.
Creatures you control have trample. (Each of those creatures can deal excess combat damage to the player or planeswalker it's attacking.)
Whenever a creature you control with power 4 or greater enters, draw a card.

Wild Growth

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

Progenitor Mimic

You may have Progenitor Mimic enter as a copy of any creature on the battlefield, except it has "At the beginning of your upkeep, if this creature isn't a token, create a token that's a copy of this creature."

Curse of the Swine

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

Primordial Hydra

Primordial Hydra enters 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.

Darksteel Ingot

Indestructible (Effects that say "destroy" don't destroy this artifact.)
{T}: Add one mana of any color.

Managorger Hydra

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

Whiptongue Hydra

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

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.

Vastwood Hydra

Vastwood Hydra enters 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.

Reyhan, Last of the Abzan

Reyhan, Last of the Abzan enters with three +1/+1 counters on it.
Whenever a creature you control dies or is put into the command zone, if it had one or more +1/+1 counters on it, you may put that many +1/+1 counters on target creature.
Partner (You can have two commanders if both have partner.)

Braingeyser

Voracious Hydra

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

To Be Removed

In Search of Greatness

At the beginning of your upkeep, you may cast a permanent spell from your hand with mana value equal to 1 plus the highest mana value among other permanents you control without paying its mana cost. If you don't, scry 1.

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.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Bellowing Tanglewurm

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Other green creatures you control have intimidate.

Vigor

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.

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 Gyre Sage.

Devoted Druid

{T}: Add {G}.
Put a -1/-1 counter on Devoted Druid: Untap Devoted Druid.

Endless One

Endless One enters with X +1/+1 counters on it.

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.

Steelbane Hydra

Steelbane Hydra enters with X +1/+1 counters on it.
{2}{G}, Remove a +1/+1 counter from Steelbane Hydra: Destroy target artifact or enchantment.

Getting

Prizefight

Target creature you control fights target creature you don't control. (Each deals damage equal to its power to the other.)
Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Hooded Hydra

Hooded Hydra enters 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.

Defense of the Heart

At the beginning of your upkeep, if an opponent controls three or more creatures, sacrifice Defense of the Heart, search your library for up to two creature cards, put those cards onto the battlefield, then shuffle.

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.

Primordial Sage

Whenever you cast a creature spell, you may draw a card.

Elvish Mystic

Mistcutter Hydra

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

Renata, Called to the Hunt

Renata's power is equal to your devotion to green. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)
Each other creature you control enters with an additional +1/+1 counter on it.

Darkmoss Bridge

Darkmoss Bridge enters tapped.
Indestructible
{T}: Add {B} or {G}.

Beastcaller Savant

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

Druids' Repository

Whenever a creature you control attacks, put a charge counter on Druids' Repository.
Remove a charge counter from Druids' Repository: Add one mana of any color.

Protean Hydra

Protean Hydra enters 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.

Three Visits

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

Hydra's Growth

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

Rampant Growth

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

Forgotten Ancient

Whenever a player casts a spell, you may put a +1/+1 counter on Forgotten Ancient.
At the beginning of your upkeep, you may move any number of +1/+1 counters from Forgotten Ancient onto other creatures.

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.)

Ironscale Hydra

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

Shamanic Revelation

Draw a card for each creature you control.
Ferocious — You gain 4 life for each creature you control with power 4 or greater.

Emerald Medallion

Green spells you cast cost {1} less to cast.

Command Tower

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.

Island

Sol Ring

Bootleggers' Stash

Lands you control have "{T}: Create a Treasure token."

Loyal Guardian

Trample
Lieutenant — At the beginning of combat on your turn, if you control your commander, put a +1/+1 counter on each creature you control.

Cultivate

Gaea's Blessing

Target player shuffles up to three target cards from their graveyard into their library.
Draw a card.
When Gaea's Blessing is put into your graveyard from your library, shuffle your graveyard into your library.

Pridemalkin

When Pridemalkin enters, put a +1/+1 counter on target creature you control.
Each creature you control with a +1/+1 counter on it has trample. (It can deal excess combat damage to the player or planeswalker it's attacking.)

Dissolve

Counter target spell. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Somberwald Sage

{T}: Add three mana of any one color. Spend this mana only to cast creature spells.

Dissipate

Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Neverwinter Hydra

As Neverwinter Hydra enters, 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}.)

Snow-Covered Forest

Vivid Creek

Vivid Creek enters tapped with two charge counters on it.
{T}: Add {U}.
{T}, Remove a charge counter from Vivid Creek: Add one mana of any color.

Exotic Orchard

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

Disruption Protocol

As an additional cost to cast this spell, tap an untapped artifact you control or pay {1}.
Counter target spell.

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.

Heroes' Bane

This creature enters with four +1/+1 counters on it.
{2}{G}{G}: Put X +1/+1 counters on this creature, where X is its power.

Kalonian Hydra

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.

Hungering Hydra

Hungering Hydra enters 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.)

Forest

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.

Beast Within

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

Vivid Grove

Vivid Grove enters tapped with two charge counters on it.
{T}: Add {G}.
{T}, Remove a charge counter from Vivid Grove: Add one mana of any color.

Naturalize

Selvala, Heart of the Wilds

Whenever another creature enters, 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.

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.

Llanowar Elves

Counterspell

Prevent all combat damage that would be dealt this turn.

Birds of Paradise

The Great Henge

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 you control enters, put a +1/+1 counter on it and draw a card.

Incubation Druid

{T}: Add one mana of any type that a land you control could produce. If Incubation Druid has a +1/+1 counter on it, add three mana of that type instead.
{3}{G}{G}: Adapt 3. (If this creature has no +1/+1 counters on it, put three +1/+1 counters on it.)

Fyndhorn Elves

Gilt-Leaf Palace

As Gilt-Leaf Palace enters, you may reveal an Elf card from your hand. If you don't, Gilt-Leaf Palace enters tapped.
{T}: Add {B} or {G}.

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.

Karametra's Acolyte

{T}: Add an amount of {G} equal to your devotion to green. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)

Wren's Run Hydra

Reach
Wren's Run Hydra enters 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.)

Stonehoof Chieftain

Trample, indestructible
Whenever another creature you control attacks, it gains trample and indestructible until end of turn.

Ilysian Caryatid

{T}: Add one mana of any color. If you control a creature with power 4 or greater, add two mana of any one color instead.

Evolving Wilds

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

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.

Cancel

Shaman of Forgotten Ways

{T}: Add two mana in any combination of colors. Spend this mana only to cast creature spells.
Formidable — {9}{G}{G}, {T}: Each player's life total becomes the number of creatures they control. Activate only if creatures you control have total power 8 or greater.

Wildwood Scourge

This creature enters 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 this creature.

Hagra Constrictor

Hagra Constrictor enters with two +1/+1 counters on it.
Each creature you control with a +1/+1 counter on it has menace. (A creature with menace can't be blocked except by two or more creatures.)