Pollywog Symbiote

Each creature spell you cast costs {1} less to cast if it has mutate.
Whenever you cast a creature spell, if it has mutate, draw a card, then discard a card.

Cabal Ritual

Add {B}{B}{B}.
Threshold — Add {B}{B}{B}{B}{B} instead if seven or more cards are in your graveyard.

Drowned Catacomb

Drowned Catacomb enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Morphic Pool

Morphic Pool enters tapped unless you have two or more opponents.
{T}: Add {U} or {B}.

Tend the Pests

As an additional cost to cast this spell, sacrifice a creature.
Create X 1/1 black and green Pest creature tokens with "When this creature dies, you gain 1 life," where X is the sacrificed creature's power.

Dreamtail Heron

Mutate {3}{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.)
Flying
Whenever this creature mutates, draw a card.

Watery Grave

({T}: Add {U} or {B}.)
As Watery Grave enters, you may pay 2 life. If you don't, it enters tapped.

Swamp

Search for Blex

Look at the top five cards of your library. You may put any number of them into your hand and the rest into your graveyard. You lose 3 life for each card you put into your hand this way.

Blex, Vexing Pest

Other Pests, Bats, Insects, Snakes, and Spiders you control get +1/+1.
When Blex, Vexing Pest dies, you gain 4 life.

Blex, Vexing Pest // Search for Blex

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.

Dirge Bat

Mutate {4}{B}{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.)
Flash
Flying
Whenever this creature mutates, destroy target creature or planeswalker an opponent controls.

Scute Swarm

Landfall — Whenever a land you control enters, create a 1/1 green Insect creature token. If you control six or more lands, create a token that's a copy of Scute Swarm instead.

Culling the Weak

As an additional cost to cast this spell, sacrifice a creature.
Add {B}{B}{B}{B}.

Farseek

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

Dina, Soul Steeper

Whenever you gain life, each opponent loses 1 life.
{1}, Sacrifice another creature: Dina, Soul Steeper gets +X/+0 until end of turn, where X is the sacrificed creature's power.

Woodland Cemetery

Woodland Cemetery enters tapped unless you control a Swamp or a Forest.
{T}: Add {B} or {G}.

Pest Infestation

Destroy up to X target artifacts and/or enchantments. Create twice X 1/1 black and green Pest creature tokens with "When this creature dies, you gain 1 life."

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Muldrotha, the Gravetide

During each of your turns, you may play a land and cast a permanent spell of each permanent type from your graveyard. (If a card has multiple permanent types, choose one as you play it.)

Plumb the Forbidden

As an additional cost to cast this spell, you may sacrifice one or more creatures. When you do, copy this spell for each creature sacrificed this way.
You draw a card and you lose 1 life.

Ukkima, Stalking Shadow

Partner with Cazur, Ruthless Stalker (When this creature enters, target player may put Cazur into their hand from their library, then shuffle.)
Ukkima, Stalking Shadow can't be blocked.
When Ukkima leaves the battlefield, it deals X damage to target player and you gain X life, where X is its power.

Plunge into Darkness

Choose one —
• Sacrifice any number of creatures. You gain 3 life for each creature sacrificed this way.
• Pay any amount of life, then look at that many cards from the top of your library. Put one of those cards into your hand and exile the rest.
Entwine {B} (Choose both if you pay the entwine cost.)

Forest

Parcelbeast

Mutate {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.)
{1}, {T}: Look at the top card of your library. If it's a land card, you may put it onto the battlefield. If you don't put the card onto the battlefield, put it into your hand.

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.

Restorative Burst

Return up to two target creature, land, and/or planeswalker cards from your graveyard to your hand. Each player gains 4 life. Exile Restorative Burst.

Pestilent Cauldron

{T}, Discard a card: Create a 1/1 black and green Pest creature token with "When this creature dies, you gain 1 life."
{1}, {T}: Each opponent mills cards equal to the amount of life you gained this turn.
{4}, {T}: Exile four target cards from a single graveyard. Draw a card.

Pestilent Cauldron // Restorative Burst

Beledros Witherbloom

Flying
At the beginning of each upkeep, create a 1/1 black and green Pest creature token with "When this creature dies, you gain 1 life."
Pay 10 life: Untap all lands you control. Activate only once each turn.

Island

Village Rites

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Yarok, the Desecrated

Deathtouch, lifelink
If a permanent entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Blossoming Bogbeast

Whenever Blossoming Bogbeast attacks, you gain 2 life. Then creatures you control gain trample and get +X/+X until end of turn, where X is the amount of life you gained this turn.

Heroic Intervention

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

Kodama of the East Tree

Reach
Whenever another permanent you control enters, if it wasn't put onto the battlefield with this ability, you may put a permanent card with equal or lesser mana value from your hand onto the battlefield.
Partner (You can have two commanders if both have partner.)

Field of the Dead

Field of the Dead enters tapped.
{T}: Add {C}.
Whenever Field of the Dead or another land you control enters, if you control seven or more lands with different names, create a 2/2 black Zombie creature token.

Culling Ritual

Destroy each nonland permanent with mana value 2 or less. Add {B} or {G} for each permanent destroyed this way.

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Lisette, Dean of the Root

Whenever you gain life, you may pay {1}. If you do, put a +1/+1 counter on each creature you control and those creatures gain trample until end of turn.

Valentin, Dean of the Vein

Menace, lifelink
If a nontoken creature an opponent controls would die, exile it instead. When you do, you may pay {2}. If you do, create a 1/1 black and green Pest creature token with "When this creature dies, you gain 1 life."

Valentin, Dean of the Vein // Lisette, Dean of the Root

Second Harvest

For each token you control, create a token that's a copy of that permanent.

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.

Mortality Spear

This spell costs {2} less to cast if you gained life this turn.
Destroy target nonland permanent.

Demonic Tutor

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

Chittering Harvester

Mutate {4}{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.)
Whenever this creature mutates, each opponent sacrifices a creature of their choice.

Undergrowth Stadium

Undergrowth Stadium enters tapped unless you have two or more opponents.
{T}: Add {B} or {G}.

Sea-Dasher Octopus

Mutate {1}{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.)
Flash
Whenever this creature deals combat damage to a player, draw a card.

Shared Summons

Search your library for up to two creature cards with different names, reveal them, put them into your hand, then shuffle.

Triumph of the Hordes

Until end of turn, creatures you control get +1/+1 and gain trample and infect. (Creatures with infect deal damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Snow-Covered Swamp

Snow-Covered Island

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.

Panharmonicon

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

Deadly Brew

Each player sacrifices a creature or planeswalker of their choice. If you sacrificed a permanent this way, you may return another permanent card from your graveyard to your hand.

Pouncing Shoreshark

Mutate {3}{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.)
Flash
Whenever this creature mutates, you may return target creature an opponent controls to its owner's hand.

Brokkos, Apex of Forever

Mutate {2}{U/B}{G}{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.)
Trample
You may cast Brokkos, Apex of Forever from your graveyard using its mutate ability.

Cultivate

Command Tower

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

Expedition Map

{2}, {T}, Sacrifice this artifact: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Auspicious Starrix

Mutate {5}{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, exile cards from the top of your library until you exile X permanent cards, where X is the number of times this creature has mutated. Put those permanent cards onto the battlefield.

Mindleecher

Mutate {4}{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.)
Flying
Whenever this creature mutates, exile the top card of each opponent's library face down. You may look at and play those cards for as long as they remain exiled.

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.

Essence Symbiote

Whenever a creature you control mutates, put a +1/+1 counter on that creature and you gain 2 life.

Diabolic Intent

As an additional cost to cast this spell, sacrifice a creature.
Search your library for a card, put that card into your hand, then shuffle.

Rushed Rebirth

Choose target creature. When that creature dies this turn, search your library for a creature card with lesser mana value, put it onto the battlefield tapped, then shuffle.

Three Visits

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

Pest Summoning

Create two 1/1 black and green Pest creature tokens with "When this creature dies, you gain 1 life."

Beast Within

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

Snow-Covered Forest

Sawtusk Demolisher

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.)
Trample
Whenever this creature mutates, destroy target noncreature permanent. Its controller creates a 3/3 green Beast creature token.

Filth

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
As long as Filth is in your graveyard and you control a Swamp, creatures you control have swampwalk.

Sedgemoor Witch

Menace
Ward—Pay 3 life. (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays 3 life.)
Magecraft — Whenever you cast or copy an instant or sorcery spell, create a 1/1 black and green Pest creature token with "When this creature dies, you gain 1 life."

Cold-Eyed Selkie

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever Cold-Eyed Selkie deals combat damage to a player, you may draw that many cards.

Daemogoth Titan

Whenever Daemogoth Titan attacks or blocks, sacrifice a creature.

Blight Mound

Attacking Pests you control get +1/+0 and have menace.
Whenever a nontoken creature you control dies, create a 1/1 black and green Pest creature token with "When this creature dies, you gain 1 life."

Gemrazer

Mutate {1}{G}{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, trample
Whenever this creature mutates, destroy target artifact or enchantment an opponent controls.

Overgrown Tomb

({T}: Add {B} or {G}.)
As Overgrown Tomb enters, you may pay 2 life. If you don't, it enters tapped.

Zagoth Triome

({T}: Add {B}, {G}, or {U}.)
Zagoth Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Eternal Witness

When Eternal Witness enters, you may return target card from your graveyard to your hand.

Altar of the Brood

Whenever another permanent you control enters, each opponent mills a card.

Tidal Barracuda

Any player may cast spells as though they had flash.
Your opponents can't cast spells during your turn.