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.

Willing Test Subject

Reach
Whenever you roll a 4 or higher on a die, put a +1/+1 counter on Willing Test Subject.
{6}: Roll a six-sided die.

Intruder Alarm

Creatures don't untap during their controllers' untap steps.
Whenever a creature enters, untap all creatures.

Humming-

Flying
Whenever you attack with two or more creatures,
Augment {3}{W} ({3}{W}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Tundra

Snake Umbra

Enchant creature
Enchanted creature gets +1/+1 and has "Whenever this creature deals damage to an opponent, you may draw a card."
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Command Tower

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

Strutting Turkey

When this creature enters,
exile target creature card with mana value 2 or less from your graveyard. If it has augment, combine it with a host you control. Otherwise, put it onto the battlefield.

Ninja

You may activate Ninja's augment ability any time you could cast an instant.
Whenever this creature deals combat damage to a player,
Augment {2}{B} ({2}{B}, Reveal this card from your hand: Combine it with target host. Augment only as—oh, never mind.)

Savannah

Dirty Rat

When this creature enters, target opponent discards a card.

Big Boa Constrictor

When this creature enters, roll a six-sided die. Target opponent loses life equal to the result.

Worldly Tutor

Search your library for a creature card, reveal it, then shuffle and put the card on top.

Dr. Julius Jumblemorph

Dr. Julius Jumblemorph is every creature type (even if this card isn't on the battlefield).
Whenever a host you control enters, you may search your library and/or graveyard for a card with augment and combine it with that host. If you search your library this way, shuffle.

Proper Laboratory Attire

Equipped creature gets +2/+1 and has protection from die rolls. (Nothing that lets a player roll a die can block, target, deal damage to, or attach to equipped creature.)
Equip {2}

Swamp

Shellephant

{0}: Choose one. You may activate this ability while Shellephant is in any zone.
• Shellephant has base power and toughness 1/4.
• Shellephant has base power and toughness 3/3.

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

Cryptolith Rite

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

Shaggy Camel

When this creature enters, creatures you control get +1/+1 until end of turn.

Eladamri's Call

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

Common Iguana

When this creature enters, you may discard a card. If you do, draw a card.

Wooded Foothills

{T}, Pay 1 life, Sacrifice Wooded Foothills: Search your library for a Mountain or Forest card, put it onto the battlefield, then shuffle.

Feisty Stegosaurus

When this creature enters, roll a six-sided die. This creature deals damage equal to the result to target creature an opponent controls.

Eldrazi Conscription

Enchant creature
Enchanted creature gets +10/+10 and has trample and annihilator 2. (Whenever it attacks, defending player sacrifices two permanents.)

Adorable Kitten

When this creature enters, roll a six-sided die. You gain life equal to the result.

Mountain

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Training Grounds

Activated abilities of creatures you control cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Cyclonic Rift

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.")

Flooded Strand

{T}, Pay 1 life, Sacrifice Flooded Strand: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Crab Umbra

Enchant creature
{2}{U}: Untap enchanted creature.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Scalding Tarn

{T}, Pay 1 life, Sacrifice Scalding Tarn: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

Tropical Island

Zombified

{4}{B}: Combine Zombified from your graveyard with target host.
{2}{B}, Exile a creature card from your graveyard:
Augment {4}{B} ({4}{B}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Monkey-

Whenever a nontoken creature you control dies,
Augment {2}{G} ({2}{G}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Multi-Headed

At the beginning of each end step, if you rolled a die this turn,
Augment {4}{G} ({4}{G}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Squirrel Dealer

When Squirrel Dealer enters, ask a person outside the game "Do you like Squirrels?" If they do, create a 1/1 green Squirrel creature token.

Half-Squirrel, Half-

Whenever a nontoken creature enters,
Augment {G} ({G}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Windswept Heath

{T}, Pay 1 life, Sacrifice Windswept Heath: Search your library for a Forest or Plains card, put it onto the battlefield, then shuffle.

Crafty Octopus

When this creature enters, this creature assembles a Contraption. (Put the top card of your Contraption deck face up onto one of your sprockets.)

Scrubland

Ineffable Blessing

As Ineffable Blessing enters, choose Flavorful or Bland.
• Flavorful — Whenever a creature with flavor text enters under your control, draw a card.
• Bland — Whenever a creature without flavor text enters under your control, draw a card.

Bayou

Secret Base

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a spell that shares a watermark with Secret Base.

Teacher's Pet

{2}{W}, Sacrifice Teacher's Pet: Search your library for a card with augment, combine it with target host you control, then shuffle.

Underdome

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to pay Un-costs.

Marsh Flats

{T}, Pay 1 life, Sacrifice Marsh Flats: Search your library for a Plains or Swamp card, put it onto the battlefield, then shuffle.

Forest

Half-Orc, Half-

Trample
At the beginning of each end step, if an opponent was dealt damage this turn,
Augment {1}{R}{R} ({1}{R}{R}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Mother Kangaroo

When this creature enters, roll a six-sided die. Put a number of +1/+1 counters on this creature equal to the result.

Bloodstained Mire

{T}, Pay 1 life, Sacrifice Bloodstained Mire: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

Badlands

Cathars' Crusade

Whenever a creature you control enters, put a +1/+1 counter on each creature you control.

Numbing Jellyfish

When this creature enters, roll a six-sided die. Target player mills X cards, where X is the result.

Staying Power

"Until end of turn" and "this turn" effects don't end.

Angelic Rocket

Flying
When this creature enters, you may destroy target nonland permanent.

Hydradoodle

As Hydradoodle enters, roll X six-sided dice. Hydradoodle enters with a number of +1/+1 counters on it equal to the total of those results.
Reach, trample

Voracious Vacuum

When this creature enters, put a +1/+1 counter on target creature.

Eager Beaver

When this creature enters, you may untap target permanent.

Bear Umbra

Enchant creature
Enchanted creature gets +2/+2 and has "Whenever this creature attacks, untap all lands you control."
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Bumbling Pangolin

When this creature enters, you may destroy target artifact.

Underground Sea

Strionic Resonator

{2}, {T}: Copy target triggered ability you control. You may choose new targets for the copy. (A triggered ability uses the words "when," "whenever," or "at.")

Reconnaissance

{0}: Remove target attacking creature you control from combat and untap it. (If you activate during end of combat, the creature will untap after it deals combat damage.)

Simic Ascendancy

{1}{G}{U}: Put a +1/+1 counter on target creature you control.
Whenever one or more +1/+1 counters are put on a creature you control, put that many growth counters on Simic Ascendancy.
At the beginning of your upkeep, if Simic Ascendancy has twenty or more growth counters on it, you win the game.

Wild Crocodile

When this creature enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Druid of the Sacred Beaker

{T}: Add {G} for each Crossbreed Labs watermark among permanents you control.

Mer Man

When this creature enters, you may draw a card.

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Frankie Peanuts

At the beginning of your upkeep, you may ask target player a yes-or-no question. If you do, that player answers the question truthfully and abides by that answer if able until end of turn.

Robo-

At the beginning of each end step, if an artifact entered the battlefield under your control this turn,
Augment {2} ({2}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Island

Steam-Powered

{5}:
Augment {4} ({4}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Gnome-Made Engine

When this creature enters, create a 1/1 colorless Gnome artifact creature token.

Misty Rainforest

{T}, Pay 1 life, Sacrifice Misty Rainforest: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

Who // What // When // Where // Why

Plains

Bat-

Flying
At the beginning of each end step, if an opponent lost 3 or more life this turn,
Augment {1}{B} ({1}{B}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Octopus Umbra

Enchant creature
Enchanted creature has base power and toughness 8/8 and has "Whenever this creature attacks, you may tap target creature with power 8 or less."
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Slaying Mantis

Just a second (As long as this spell is on the stack, players can't move permanents.)
Slaying Mantis enters by being thrown from a distance of at least three feet.
When Slaying Mantis enters, it fights each creature an opponent controls that it touched as it entered.

Plateau

Half-Shark, Half-

At the beginning of your upkeep,
Augment {5}{U} ({5}{U}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Arid Mesa

{T}, Pay 1 life, Sacrifice Arid Mesa: Search your library for a Mountain or Plains card, put it onto the battlefield, then shuffle.

Taiga

Demonic Tutor

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

Clever Combo

Search your library for a host card or a card with augment, reveal it, put it into your hand, then shuffle.

Volcanic Island

Stinging Scorpion

When this creature enters, target creature an opponent controls gets -1/-1 until end of turn.

Ordinary Pony

When this creature enters, you may exile target non-Horse creature you control that wasn't put onto the battlefield with this ability this turn, then return it to the battlefield under its owner's control.

Polluted Delta

{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Serpentine

Landfall — Whenever a land you control enters,
Augment {2}{G} ({2}{G}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Sword of Dungeons & Dragons

Equipped creature gets +2/+2 and has protection from Rogues and from Clerics.
Whenever equipped creature deals combat damage to a player, create a 4/4 gold Dragon creature token with flying and roll a d20 (a twenty-sided die). If you roll a 20, repeat this process.
Equip {2}

Half-Kitten, Half-

Whenever you're dealt damage,
Augment {2}{W} ({2}{W}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Rhino-

Whenever this creature blocks,
Augment {3}{W} ({3}{W}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Surgeon General Commander

Whenever you augment, enchant, or mutate a creature you control, draw a card.
{T}: Add {W}, {U}, {B}, {R}, or {G}.

Labro Bot

When this creature enters, return target host card or card with augment from your graveyard to your hand.

Verdant Catacombs

{T}, Pay 1 life, Sacrifice Verdant Catacombs: Search your library for a Swamp or Forest card, put it onto the battlefield, then shuffle.