Chromanticore

Bestow {2}{W}{U}{B}{R}{G} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Flying, first strike, vigilance, trample, lifelink
Enchanted creature gets +4/+4 and has flying, first strike, vigilance, trample, and lifelink.

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.)

Frontier Bivouac

This land enters tapped.
{T}: Add {G}, {U}, or {R}.

Hypnotic Siren

Bestow {5}{U}{U} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Flying
You control enchanted creature.
Enchanted creature gets +1/+1 and has flying.

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.

Surgeon General Commander

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

Sol Ring

Jack-in-the-Mox

{T}: Roll a six-sided die. This ability has the indicated effect.
1 — Sacrifice this artifact and you lose 5 life.
2 — Add {W}.
3 — Add {U}.
4 — Add {B}.
5 — Add {R}.
6 — Add {G}.

Cubwarden

Mutate {2}{W}{W} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Lifelink
Whenever this creature mutates, create two 1/1 white Cat creature tokens with lifelink.

Arcane Sanctum

This land enters tapped.
{T}: Add {W}, {U}, or {B}.

Otrimi, the Ever-Playful

Mutate {1}{B}{G}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Trample
Whenever this creature deals combat damage to a player, return target creature card with mutate from your graveyard to your hand.

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.)

Forest

Numbing Jellyfish

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

Underdome

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

Observant Alseid

Bestow {4}{W} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Vigilance
Enchanted creature gets +2/+2 and has vigilance.

Labro Bot

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

Cavern Whisperer

Mutate {3}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Menace (This creature can't be blocked except by two or more creatures.)
Whenever this creature mutates, each opponent discards a card.

The Mimeoplasm

As The Mimeoplasm enters, you may exile two creature cards from graveyards. If you do, it enters as a copy of one of those cards with a number of additional +1/+1 counters on it equal to the power of the other card.

Hanna, Ship's Navigator

{1}{W}{U}, {T}: Return target artifact or enchantment card from your graveyard to your hand.

Insatiable Hemophage

Mutate {2}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Deathtouch
Whenever this creature mutates, each opponent loses X life and you gain X life, where X is the number of times this creature has mutated.

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.)

Kestia, the Cultivator

Bestow {3}{G}{W}{U} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Enchanted creature gets +4/+4.
Whenever an enchanted creature or enchantment creature you control attacks, draw a card.

Baleful Eidolon

Bestow {4}{B} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Enchanted creature gets +1/+1 and has deathtouch.

Vulpikeet

Mutate {2}{W} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flying
Whenever this creature mutates, put a +1/+1 counter on it.

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.

Seaside Citadel

This land enters tapped.
{T}: Add {G}, {W}, or {U}.

Selfie Preservation

Search your library for a basic land card and reveal it. If there's a tree in its art, put it onto the battlefield tapped. Otherwise, put it into your hand. Then shuffle.

Mad Science Fair Project

{T}: Roll a six-sided die. On a 3 or lower, target player adds {C}. Otherwise, that player adds one mana of any color they choose.

Roadside Reliquary

{T}: Add {C}.
{2}, {T}, Sacrifice this land: Draw a card if you control an artifact. Draw a card if you control an enchantment.

Hyena Umbra

Enchant creature
Enchanted creature gets +1/+1 and has first strike.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Eel Umbra

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature gets +1/+1.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Guardian's Magemark

Flash
Enchant creature
Creatures you control that are enchanted get +1/+1.

Boneyard Lurker

Mutate {2}{B/G}{B/G} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, return target permanent card from your graveyard to your hand.

Voracious Vacuum

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

Nyxborn Rollicker

Bestow {1}{R} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Enchanted creature gets +1/+1.

Infiltrator's Magemark

Enchant creature
Creatures you control that are enchanted get +1/+1 and can't be blocked except by creatures with defender.

Bumbling Pangolin

When this creature enters, you may destroy target artifact.

Terramorphic Expanse

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

Plains

Callaphe, Beloved of the Sea

Callaphe's power is equal to your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)
Creatures and enchantments you control have "Spells your opponents cast that target this permanent cost {1} more to cast."

Gnome-Made Engine

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

Flock of Rabid Sheep

Flip X coins. For each flip you win, create a 2/2 green Sheep creature token named Rabid Sheep.

Snapdax, Apex of the Hunt

Mutate {2}{B/R}{W}{W} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Double strike
Whenever this creature mutates, it deals 4 damage to target creature or planeswalker an opponent controls and you gain 4 life.

Migratory Greathorn

Mutate {2}{G} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

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.)

Evolving Wilds

Nomad Outpost

This land enters tapped.
{T}: Add {R}, {W}, or {B}.

Haunted Fengraf

{T}: Add {C}.
{3}, {T}, Sacrifice this land: Return a creature card at random from your graveyard to your hand.

Noble Quarry

Bestow {5}{G} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
All creatures able to block this creature or enchanted creature do so.
Enchanted creature gets +1/+1.

Eidolon of Countless Battles

Bestow {2}{W}{W} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
This creature and enchanted creature each get +1/+1 for each creature you control and +1/+1 for each Aura you control.

Beastmaster's Magemark

Enchant creature
Creatures you control that are enchanted get +1/+1.
Whenever a creature you control that's enchanted becomes blocked, it gets +1/+1 until end of turn for each creature blocking it.

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.)

Wild Crocodile

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

Swamp

Grusilda, Monster Masher

Combined, enchanted, and equipped creatures you control have menace.
{3}{B}{R}, {T}: Put two target creature cards from graveyards onto the battlefield combined into one creature under your control. (Its power is equal to their total power, its toughness is equal to their total toughness, and it has their names, mana costs, types, text boxes, etc.)

Glowstone Recluse

Mutate {3}{G} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Reach
Whenever this creature mutates, put two +1/+1 counters on it.

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

Mystic Monastery

This land enters tapped.
{T}: Add {U}, {R}, or {W}.

Sandsteppe Citadel

This land enters tapped.
{T}: Add {W}, {B}, or {G}.

Estrid, the Masked

+2: Untap each enchanted permanent you control.
−1: Create a white Aura enchantment token named Mask attached to another target permanent. The token has enchant permanent and umbra armor.
−7: Mill seven cards. Return all non-Aura enchantment cards from your graveyard to the battlefield, then do the same for Aura cards.
Estrid, the Masked can be your commander.

Trumpeting Gnarr

Mutate {3}{G/U}{G/U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, create a 3/3 green Beast creature token.

Mountain

Nighthowler

Bestow {2}{B}{B} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
This creature and enchanted creature each get +X/+X, where X is the number of creature cards in all graveyards.

Ninja

You may activate this card'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.)

Archipelagore

Mutate {5}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, tap up to X target creatures, where X is the number of times this creature has mutated. Those creatures don't untap during their controller's next untap step.

Crumbling Necropolis

This land enters tapped.
{T}: Add {U}, {B}, or {R}.

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.)

Rupture Spire

This land enters tapped.
When this land enters, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Big Boa Constrictor

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

Opulent Palace

This land enters tapped.
{T}: Add {B}, {G}, or {U}.

Island

Really Epic Punch

Target creature you control gets +2/+2 if it's a host or has augment. Then it fights target creature you don't control.

Steam-Powered

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

Command Tower

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

Savage Lands

This land enters tapped.
{T}: Add {B}, {R}, or {G}.

Oddly Uneven

Choose one —
• Destroy each creature with an odd number of words in its name. (Hyphenated words are one word.)
• Destroy each creature with an even number of words in its name.

Shimmering Grotto

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Clever Combo

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

Urza, Academy Headmaster

+1: Head to AskUrza.com and click +1.
−1: Head to AskUrza.com and click -1.
−6: Head to AskUrza.com and click -6.

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.)

Boar Umbra

Enchant creature
Enchanted creature gets +3/+3.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Huntmaster Liger

Mutate {2}{W} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, other creatures you control get +X/+X until end of turn, where X is the number of times this creature has mutated.