Pir, Imaginative Rascal

Partner with Toothy, Imaginary Friend (When this creature enters, target player may put Toothy into their hand from their library, then shuffle.)
If one or more counters would be put on a permanent your team controls, that many plus one of each of those kinds of counters are put on that permanent instead.

Forest

Tome Raider

Flying
When Tome Raider enters, draw a card.

Shield's Might

Target creature gets +2/+2 until end of turn. (Then exile this card. You may cast the creature later from exile.)

Garenbrig Carver

Garenbrig Carver // Shield's Might

Maraleaf Pixie

Bramblefort Fink

{8}: Bramblefort Fink has base power and toughness 10/10 until end of turn. Activate only if you control an Oko planeswalker.

Arixmethes, Slumbering Isle

Arixmethes, Slumbering Isle enters tapped with five slumber counters on it.
As long as Arixmethes has a slumber counter on it, it's a land. (It's not a creature.)
Whenever you cast a spell, you may remove a slumber counter from Arixmethes.
{T}: Add {G}{U}.

Faerie Vandal

Flash (You may cast this spell any time you could cast an instant.)
Flying
Whenever you draw your second card each turn, put a +1/+1 counter on Faerie Vandal.

Island

Fertile Footsteps

Search your library for a basic land card, put it onto the battlefield, then shuffle. (Then exile this card. You may cast the creature later from exile.)

Beanstalk Giant

Beanstalk Giant's power and toughness are each equal to the number of lands you control.

Beanstalk Giant // Fertile Footsteps

Oaken Boon

Put two +1/+1 counters on target creature. (Then exile this card. You may cast the creature later from exile.)

Tuinvale Treefolk

Tuinvale Treefolk // Oaken Boon

Chasm Skulker

Whenever you draw a card, put a +1/+1 counter on Chasm Skulker.
When Chasm Skulker dies, create X 1/1 blue Squid creature tokens with islandwalk, where X is the number of +1/+1 counters on Chasm Skulker. (They can't be blocked as long as defending player controls an Island.)

Wildborn Preserver

Flash (You may cast this spell any time you could cast an instant.)
Reach (This creature can block creatures with flying.)
Whenever another non-Human creature you control enters, you may pay {X}. When you do, put X +1/+1 counters on this creature.

Mistford River Turtle

Whenever Mistford River Turtle attacks, another target attacking non-Human creature can't be blocked this turn.

Kodama of the West Tree

Reach
Modified creatures you control have trample. (Equipment, Auras you control, and counters are modifications.)
Whenever a modified creature you control deals combat damage to a player, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Frogify

Enchant creature
Enchanted creature loses all abilities and is a blue Frog creature with base power and toughness 1/1. (It loses all other card types and creature types.)

Gilder Bairn

{2}{G/U}, {Q}: Double the number of each kind of counter on target permanent. ({Q} is the untap symbol.)

Thundering Mightmare

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Thundering Mightmare is paired with another creature, each of those creatures has "Whenever an opponent casts a spell, put a +1/+1 counter on this creature."

Managorger Hydra

Trample
Whenever a player casts a spell, put a +1/+1 counter on Managorger Hydra.

Oko's Hospitality

Creatures you control have base power and toughness 3/3 until end of turn. You may search your library and/or graveyard for a card named Oko, the Trickster, reveal it, and put it into your hand. If you search your library this way, shuffle.

Toothy, Imaginary Friend

Partner with Pir, Imaginative Rascal (When this creature enters, target player may put Pir into their hand from their library, then shuffle.)
Whenever you draw a card, put a +1/+1 counter on Toothy, Imaginary Friend.
When Toothy leaves the battlefield, draw a card for each +1/+1 counter on it.

Thornwood Falls

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {G} or {U}.

Hollowhenge Huntmaster

Hexproof
Other permanents you control have hexproof.
At the beginning of combat on your turn, put two +1/+1 counters on each creature you control.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Avabruck Caretaker

Hexproof
At the beginning of combat on your turn, put two +1/+1 counters on another target creature you control.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Avabruck Caretaker // Hollowhenge Huntmaster

Oko, the Trickster

+1: Put two +1/+1 counters on up to one target creature you control.
0: Until end of turn, Oko, the Trickster becomes a copy of target creature you control. Prevent all damage that would be dealt to him this turn.
−7: Until end of turn, each creature you control has base power and toughness 10/10 and gains trample.

Vorel of the Hull Clade

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

Return of the Wildspeaker

Choose one —
• Draw cards equal to the greatest power among non-Human creatures you control.
• Non-Human creatures you control get +3/+3 until end of turn.

Kalonian Hydra

Trample
Kalonian Hydra enters with four +1/+1 counters on it.
Whenever Kalonian Hydra attacks, double the number of +1/+1 counters on each creature you control.

Oko's Accomplices

Keeper of Fables

Whenever one or more non-Human creatures you control deal combat damage to a player, draw a card.

Charmed Sleep

Enchant creature
When Charmed Sleep enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.