Dead Weight

Enchant creature
Enchanted creature gets -2/-2.

Frost Lynx

When Frost Lynx enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Zagoth Mamba

Whenever this creature mutates, target creature an opponent controls gets -2/-2 until end of turn.

Zagoth Crystal

{T}: Add {B}, {G}, or {U}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Barrier Breach

Exile up to three target enchantments.
Cycling {2} ({2}, Discard this card: Draw a card.)

Farfinder

Vigilance
When Farfinder enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Anticipate

Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Humble Naturalist

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

Essence Symbiote

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

Ominous Seas

Whenever you draw a card, put a foreshadow counter on Ominous Seas.
Remove eight foreshadow counters from Ominous Seas: Create an 8/8 blue Kraken creature token.
Cycling {2} ({2}, Discard this card: Draw a card.)

Glimmerbell

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.

Dismal Backwater

Dismal Backwater enters tapped.
When Dismal Backwater enters, you gain 1 life.
{T}: Add {U} or {B}.

Emergent Ultimatum

Search your library for up to three monocolored cards with different names and exile them. An opponent chooses one of those cards. Shuffle that card into your library. You may cast the other cards without paying their mana costs. Exile Emergent Ultimatum.

Adventurous Impulse

Look at the top three cards of your library. You may reveal a creature or land card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Memory Leak

Target opponent reveals their hand. You choose a nonland card from that player's graveyard or hand and exile it.
Cycling {1} ({1}, Discard this card: Draw a card.)

Mysterious Egg

Whenever this creature mutates, put a +1/+1 counter on it.

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.

Serrated Scorpion

When Serrated Scorpion dies, it deals 2 damage to each opponent and you gain 2 life.

Bastion of Remembrance

When Bastion of Remembrance enters, create a 1/1 white Human Soldier creature token.
Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.

Grimdancer

Grimdancer enters with your choice of two different counters on it from among menace, deathtouch, and lifelink.

Island

Blitz Leech

Flash
When Blitz Leech enters, target creature an opponent controls gets -2/-2 until end of turn. Remove all counters from that creature.

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.

Nightsquad Commando

When Nightsquad Commando enters, if you attacked this turn, create a 1/1 white Human Soldier creature token.

Honey Mammoth

When Honey Mammoth enters, you gain 4 life.

Convolute

Counter target spell unless its controller pays {4}.

Cunning Nightbonder

Flash
Spells with flash you cast cost {1} less to cast and can't be countered.

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.

Heartless Act

Choose one —
• Destroy target creature with no counters on it.
• Remove up to three counters from target creature.

Mystic Subdual

Flash
Enchant creature
Enchanted creature gets -2/-0 and loses all abilities. (Mutating onto the creature won't give it new abilities. It can gain abilities in other ways.)

Skull Prophet

{T}: Add {B} or {G}.
{T}: Mill two cards.

Aegis Turtle

Flycatcher Giraffid

Flycatcher Giraffid enters with your choice of a vigilance counter or a reach counter on it.

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.

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.

Boon of the Wish-Giver

Draw four cards.
Cycling {1} ({1}, Discard this card: Draw a card.)

Sleeper Dart

When Sleeper Dart enters, draw a card.
{T}, Sacrifice Sleeper Dart: Target creature doesn't untap during its controller's next untap step.

Wingspan Mentor

When Wingspan Mentor enters, put a flying counter on target non-Human creature you control.
{2}{U}, {T}: Put a +1/+1 counter on each creature you control with flying.