Counterspell

Merfolk Skydiver

Flying
When Merfolk Skydiver enters the battlefield, put a +1/+1 counter on target creature you control.
{3}{G}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Krasis Incubation

Enchant creature
Enchanted creature can't attack or block, and its activated abilities can't be activated.
{1}{G}{U}, Return Krasis Incubation to its owner's hand: Put two +1/+1 counters on enchanted creature.

Wooded Ridgeline

({T}: Add {R} or {G}.)
Wooded Ridgeline enters the battlefield tapped.

Bant Panorama

{T}: Add {C}.
{1}, {T}, Sacrifice Bant Panorama: Search your library for a basic Forest, Plains, or Island card, put it onto the battlefield tapped, then shuffle.

Lorescale Coatl

Whenever you draw a card, put a +1/+1 counter on Lorescale Coatl.

Ainok Bond-Kin

Outlast {1}{W} ({1}{W}, {T}: Put a +1/+1 counter on this creature. Outlast only as a sorcery.)
Each creature you control with a +1/+1 counter on it has first strike.

Sage's Row Denizen

Whenever another blue creature enters the battlefield under your control, target player mills two cards.

Ivy Lane Denizen

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

Zameck Guildmage

{G}{U}: This turn, each creature you control enters the battlefield with an additional +1/+1 counter on it.
{G}{U}, Remove a +1/+1 counter from a creature you control: Draw a card.

Giant Growth

Target creature gets +3/+3 until end of turn.

Jungle Shrine

Jungle Shrine enters the battlefield tapped.
{T}: Add {R}, {G}, or {W}.

Island

Steel Leaf Paladin

First strike
When Steel Leaf Paladin enters the battlefield, return a green or white creature you control to its owner's hand.

Gateway Plaza

Gateway Plaza enters the battlefield tapped.
When Gateway Plaza enters the battlefield, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Blossoming Sands

Blossoming Sands enters the battlefield tapped.
When Blossoming Sands enters the battlefield, you gain 1 life.
{T}: Add {G} or {W}.

Carefree Swinemaster

Whenever Carefree Swinemaster attacks, you may pay {1}{G}. If you do, create a 2/2 green Boar creature token that's tapped and attacking.

Square Up

Target creature has base power and toughness 4/4 until end of turn.

Huatli's Raptor

Vigilance
When Huatli's Raptor enters the battlefield, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

River Hoopoe

Flying
{3}{G}{U}: You gain 2 life and draw a card.

Simic Signet

Plains

Agent of Horizons

{2}{U}: Agent of Horizons can't be blocked this turn.

Traitorous Instinct

Gain control of target creature until end of turn. Untap that creature. Until end of turn, it gets +2/+0 and gains haste.

Malamet Veteran

Trample
Descend 4 — Whenever Malamet Veteran attacks, if there are four or more permanent cards in your graveyard, put a +1/+1 counter on target creature.

Grasslands

Grasslands enters the battlefield tapped.
{T}, Sacrifice Grasslands: Search your library for a Forest or Plains card, put it onto the battlefield, then shuffle.

Pathfinding Axejaw

When Pathfinding Axejaw enters the battlefield, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

Burning-Tree Emissary

When Burning-Tree Emissary enters the battlefield, add {R}{G}.

Power Sink

Counter target spell unless its controller pays {X}. If that player doesn't, they tap all lands with mana abilities they control and lose all unspent mana.

Forest

Dog Walker

Vigilance
Disguise {R/W}{R/W} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)
When Dog Walker is turned face up, create two tapped 1/1 white Dog creature tokens.

Bred for the Hunt

Whenever a creature you control with a +1/+1 counter on it deals combat damage to a player, you may draw a card.

Oblivion Ring

When Oblivion Ring enters the battlefield, exile another target nonland permanent.
When Oblivion Ring leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Foresee

Thornwood Falls

Thornwood Falls enters the battlefield tapped.
When Thornwood Falls enters the battlefield, you gain 1 life.
{T}: Add {G} or {U}.

Glacial Floodplain

({T}: Add {W} or {U}.)
Glacial Floodplain enters the battlefield tapped.

Sigil Blessing

Until end of turn, target creature you control gets +3/+3 and other creatures you control get +1/+1.

Keldon Warlord

Keldon Warlord's power and toughness are each equal to the number of non-Wall creatures you control.

Snapping Gnarlid

Landfall — Whenever a land enters the battlefield under your control, Snapping Gnarlid gets +1/+1 until end of turn.

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.