Miming Slime

Create an X/X green Ooze creature token, where X is the greatest power among creatures you control.

Battering Krasis

Trample
Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Renegade Krasis

Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever Renegade Krasis evolves, put a +1/+1 counter on each other creature you control with a +1/+1 counter on it.

Forced Adaptation

Enchant creature
At the beginning of your upkeep, put a +1/+1 counter on enchanted creature.

Take

Remove all +1/+1 counters from target creature you control. Draw that many cards.
Fuse (You may cast one or both halves of this card from your hand.)

Give

Put three +1/+1 counters on target creature.
Fuse (You may cast one or both halves of this card from your hand.)

Give // Take

Cloudfin Raptor

Flying
Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Sapphire Drake

Flying
Each creature you control with a +1/+1 counter on it has flying.

Prime Speaker Zegana

Prime Speaker Zegana enters the battlefield with X +1/+1 counters on it, where X is the greatest power among other creatures you control.
When Prime Speaker Zegana enters the battlefield, draw cards equal to its power.

Experiment One

Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Remove two +1/+1 counters from Experiment One: Regenerate Experiment One. (The next time this creature would be destroyed, instead tap it, remove it from combat, and heal all damage on it.)

Mutant's Prey

Target creature you control with a +1/+1 counter on it fights target creature an opponent controls. (Each deals damage equal to its power to the other.)

Naturalize

Biomass Mutation

Creatures you control have base power and toughness X/X until end of turn.

Ooze Flux

{1}{G}, Remove one or more +1/+1 counters from among creatures you control: Create an X/X green Ooze creature token, where X is the number of +1/+1 counters removed this way.

Evolution Sage

Landfall — Whenever a land enters the battlefield under your control, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Simic Manipulator

Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
{T}, Remove one or more +1/+1 counters from Simic Manipulator: Gain control of target creature with power less than or equal to the number of +1/+1 counters removed this way.

Simic Cluestone

{T}: Add {G} or {U}.
{G}{U}, {T}, Sacrifice Simic Cluestone: Draw a card.

Incubation Druid

{T}: Add one mana of any type that a land you control could produce. If Incubation Druid has a +1/+1 counter on it, add three mana of that type instead.
{3}{G}{G}: Adapt 3. (If this creature has no +1/+1 counters on it, put three +1/+1 counters on it.)

Crocanura

Reach (This creature can block creatures with flying.)
Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Spell Rupture

Counter target spell unless its controller pays {X}, where X is the greatest power among creatures you control.

Simic Guildgate

Simic Guildgate enters the battlefield tapped.
{T}: Add {G} or {U}.

Master Biomancer

Each other creature you control enters the battlefield with a number of additional +1/+1 counters on it equal to Master Biomancer's power and as a Mutant in addition to its other types.

Bioshift

Move any number of +1/+1 counters from target creature onto another target creature with the same controller.

Vorel of the Hull Clade

{G}{U}, {T}: Double the number of each kind of counter on target artifact, creature, or land.

Crowned Ceratok

Trample
Each creature you control with a +1/+1 counter on it has trample.

Benthic Biomancer

{1}{U}: Adapt 1. (If this creature has no +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever one or more +1/+1 counters are put on Benthic Biomancer, draw a card, then discard a card.

Fertilid

Fertilid enters the battlefield with two +1/+1 counters on it.
{1}{G}, Remove a +1/+1 counter from Fertilid: Target player searches their library for a basic land card, puts it onto the battlefield tapped, then shuffles.

Fathom Mage

Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever a +1/+1 counter is put on Fathom Mage, you may draw a card.

Verdant Haven

Enchant land
When Verdant Haven enters the battlefield, you gain 2 life.
Whenever enchanted land is tapped for mana, its controller adds an additional one mana of any color.

Simic Keyrune

{T}: Add {G} or {U}.
{G}{U}: Simic Keyrune becomes a 2/3 green and blue Crab artifact creature with hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Gyre Sage

Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
{T}: Add {G} for each +1/+1 counter on Gyre Sage.

Ivy Lane Denizen

Whenever another green creature enters the battlefield under your control, put a +1/+1 counter on target creature.

Adaptive Snapjaw

Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Guardian Project

Whenever a nontoken creature enters the battlefield under your control, if it doesn't have the same name as another creature you control or a creature card in your graveyard, draw a card.

Breeding Pool

({T}: Add {G} or {U}.)
As Breeding Pool enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.