Ecologist's Terrarium

When Ecologist's Terrarium enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.
{2}, {T}, Sacrifice Ecologist's Terrarium: Put a +1/+1 counter on target creature. Activate only as a sorcery.

Tangle Golem

Affinity for Forests (This spell costs {1} less to cast for each Forest you control.)

Managorger Hydra

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

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.

Verdurous Gearhulk

Trample
When Verdurous Gearhulk enters, distribute four +1/+1 counters among any number of target creatures you control.

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.)

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

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.)

Sol Ring

Rampant Growth

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

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.

Primal Rage

Creatures you control have trample. (A creature with trample can deal excess combat damage to the player or planeswalker it's attacking.)

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.

Lifecrafter's Bestiary

At the beginning of your upkeep, scry 1.
Whenever you cast a creature spell, you may pay {G}. If you do, draw a card.

Rampant Rejuvenator

Rampant Rejuvenator enters with two +1/+1 counters on it.
When Rampant Rejuvenator dies, search your library for up to X basic land cards, where X is Rampant Rejuvenator's power, put them onto the battlefield, then shuffle.

Oran-Rief Hydra

Trample
Landfall — Whenever a land you control enters, 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.

Omnath, Locus of Mana

You don't lose unspent green mana as steps and phases end.
Omnath, Locus of Mana gets +1/+1 for each unspent green mana you have.

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.

Elemental Bond

Whenever a creature you control with power 3 or greater enters, draw a card.

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Clockwork Hydra

Clockwork Hydra enters with four +1/+1 counters on it.
Whenever Clockwork Hydra attacks or blocks, remove a +1/+1 counter from it. If you do, Clockwork Hydra deals 1 damage to any target.
{T}: Put a +1/+1 counter on Clockwork Hydra.

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.)

Rosethorn Halberd

When Rosethorn Halberd enters, attach it to target non-Human creature you control.
Equipped creature gets +2/+1.
Equip {5} ({5}: Attach to target creature you control. Equip only as a sorcery.)

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.

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.

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.

Castle Garenbrig

Castle Garenbrig enters 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.

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.

Careful Cultivation

Enchant artifact or creature
As long as enchanted permanent is a creature, it gets +1/+3 and has reach and "{T}: Add {G}{G}."
Channel — {1}{G}, Discard Careful Cultivation: Create a 1/1 green Human Monk creature token with "{T}: Add {G}."

Honored Hydra

Trample
Embalm {3}{G} ({3}{G}, Exile this card from your graveyard: Create a token that's a copy of it, except it's a white Zombie Snake Hydra with no mana cost. Embalm only as a sorcery.)

Llanowar Elves

Ancient Animus

Put a +1/+1 counter on target creature you control if it's legendary. Then it fights target creature an opponent controls. (Each deals damage equal to its power to the other.)

Hardened Scales

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.

Rancor

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

Harmonize

Strength in Numbers

Until end of turn, target creature gains trample and gets +X/+X, where X is the number of attacking creatures.

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.

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.

Burgeoning

Whenever an opponent plays a land, you may put a land card from your hand onto the battlefield.

Yavimaya Hollow

{T}: Add {C}.
{G}, {T}: Regenerate target creature.

Automatic Librarian

When Automatic Librarian enters, scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Aspect of Hydra

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.)

Unnatural Growth

At the beginning of each combat, double the power and toughness of each creature you control until end of turn.

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.)

Iron Apprentice

Iron Apprentice enters with a +1/+1 counter on it.
When Iron Apprentice dies, if it had counters on it, put those counters on target creature you control.

Triumph of Ferocity

At the beginning of your upkeep, draw a card if you control the creature with the greatest power or tied for the greatest power.

Mirran Mettle

Target creature gets +2/+2 until end of turn.
Metalcraft — That creature gets +4/+4 until end of turn instead if you control three or more artifacts.

Oran-Rief, the Vastwood

Oran-Rief, the Vastwood enters tapped.
{T}: Add {G}.
{T}: Put a +1/+1 counter on each green creature that entered this turn.

Forest

Towashi Guide-Bot

When Towashi Guide-Bot enters, put a +1/+1 counter on target creature you control.
{4}, {T}: Draw a card. This ability costs {1} less to activate for each modified creature you control. (Equipment, Auras you control, and counters are modifications.)

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.

Walking Skyscraper

This spell costs {1} less to cast for each modified creature you control. (Equipment, Auras you control, and counters are modifications.)
Trample
Walking Skyscraper has hexproof as long as it's untapped. (It can't be the target of spells or abilities your opponents control.)

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, World Eater 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.

Regeneration

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
{G}: Regenerate enchanted creature. (The next time that creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

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.

Scourge of Skola Vale

Trample
Scourge of Skola Vale enters with two +1/+1 counters on it.
{T}, Sacrifice another creature: Put a number of +1/+1 counters on Scourge of Skola Vale equal to the sacrificed creature's toughness.

Gauntlet of Power

As Gauntlet of Power enters, choose a color.
Creatures of the chosen color get +1/+1.
Whenever a basic land is tapped for mana of the chosen color, its controller adds an additional one mana of that color.

Spiked Ripsaw

Equipped creature gets +3/+3.
Whenever equipped creature attacks, you may sacrifice a Forest. If you do, that creature gains trample until end of turn.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

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.

Khalni Hydra

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

Horned Helm

Equipped creature gets +1/+1 and has trample.
{G}{G}: Attach Horned Helm to target creature you control.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Nessian Wilds Ravager

Tribute 6 (As this creature enters, an opponent of your choice may put six +1/+1 counters on it.)
When Nessian Wilds Ravager enters, if tribute wasn't paid, you may have Nessian Wilds Ravager fight another target creature. (Each deals damage equal to its power to the other.)

Mirri's Guile

At the beginning of your upkeep, you may look at the top three cards of your library, then put them back in any order.