Sludge Monster

Whenever Sludge Monster enters or attacks, put a slime counter on up to one other target creature.
Non-Horror creatures with slime counters on them lose all abilities and have base power and toughness 2/2.

Vortex Runner

As long as you control eight or more lands, Vortex Runner gets +1/+0 and can't be blocked.

Negate

Hamlet Vanguard

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Hamlet Vanguard enters with two +1/+1 counters on it for each other nontoken Human you control.

Jaspera Sentinel

Reach
{T}, Tap an untapped creature you control: Add one mana of any color.

Master Symmetrist

Reach
Whenever a creature you control with power equal to its toughness attacks, it gains trample until end of turn.

Campus Guide

When this creature enters, you may search your library for a basic land card, reveal it, then shuffle and put that card on top.

Renata, Called to the Hunt

Renata's power is equal to your devotion to green. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)
Each other creature you control enters with an additional +1/+1 counter on it.

Forest

Soothsayer Adept

{1}{U}, {T}: Draw a card, then discard a card.

Quandrix Command

Choose two —
• Return target creature or planeswalker to its owner's hand.
• Counter target artifact or enchantment spell.
• Put two +1/+1 counters on target creature.
• Target player shuffles up to three target cards from their graveyard into their library.

Herd Baloth

Whenever one or more +1/+1 counters are put on Herd Baloth, you may create a 4/4 green Beast creature token.

Arbor Elf

Armorcraft Judge

When Armorcraft Judge enters, draw a card for each creature you control with a +1/+1 counter on it.

Quandrix Campus

Quandrix Campus enters tapped.
{T}: Add {G} or {U}.
{4}, {T}: Scry 1.

Strategic Planning

Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.

Thirst for Knowledge

Draw three cards. Then discard two cards unless you discard an artifact card.

Vorinclex, Monstrous Raider

Trample, haste
If you would put one or more counters on a permanent or player, put twice that many of each of those kinds of counters on that permanent or player instead.
If an opponent would put one or more counters on a permanent or player, they put half that many of each of those kinds of counters on that permanent or player instead, rounded down.

Fertilid

Fertilid enters 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.

Selvala's Stampede

Council's dilemma — Starting with you, each player votes for wild or free. Reveal cards from the top of your library until you reveal a creature card for each wild vote. Put those creature cards onto the battlefield, then shuffle the rest into your library. You may put a permanent card from your hand onto the battlefield for each free vote.

Rooftop Saboteurs

Flying
Whenever Rooftop Saboteurs deals combat damage to a player or battle, draw a card.

Invasion of Kamigawa

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Kamigawa enters, tap target artifact or creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Invasion of Kamigawa // Rooftop Saboteurs

Golden Ratio

Draw a card for each different power among creatures you control.

Inspiring Call

Draw a card for each creature you control with a +1/+1 counter on it. Those creatures gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

Thirst for Discovery

Draw three cards. Then discard two cards unless you discard a basic land card.

Rimewood Falls

({T}: Add {G} or {U}.)
Rimewood Falls enters tapped.

Aetherize

Return all attacking creatures to their owner's hand.

Double Major

Copy target creature spell you control, except it isn't legendary if the spell is legendary. (A copy of a creature spell becomes a token.)

Arcane Signet

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

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Rampaging Rendhorn

Riot (This creature enters with your choice of a +1/+1 counter or haste.)

Opal Palace

{T}: Add {C}.
{1}, {T}: Add one mana of any color in your commander's color identity. If you spend this mana to cast your commander, it enters with a number of additional +1/+1 counters on it equal to the number of times it's been cast from the command zone this game.

Imperious Perfect

Other Elves you control get +1/+1.
{G}, {T}: Create a 1/1 green Elf Warrior creature token.

Guild Thief

Whenever Guild Thief deals combat damage to a player, put a +1/+1 counter on it.
Cunning Action — {3}{U}: Guild Thief can't be blocked this turn.

Shimmerdrift Vale

Shimmerdrift Vale enters tapped.
As Shimmerdrift Vale enters, choose a color.
{T}: Add one mana of the chosen color.

Ulvenwald Behemoth

Trample, haste
Other creatures you control get +1/+1 and have trample and haste.

Ulvenwald Oddity

Trample, haste
{5}{G}{G}: Transform Ulvenwald Oddity.

Ulvenwald Oddity // Ulvenwald Behemoth

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Rejuvenating Springs

Rejuvenating Springs enters tapped unless you have two or more opponents.
{T}: Add {G} or {U}.

Faceless Haven

{T}: Add {C}.
{S}{S}{S}: Faceless Haven becomes a 4/3 creature with vigilance and all creature types until end of turn. It's still a land. ({S} can be paid with one mana from a snow source.)

Big Play

Target creature gets +2/+2 and gains reach until end of turn. Put a +1/+1 counter on it. (A creature with reach can block creatures with flying.)

Field Trip

Search your library for a basic Forest card, put that card onto the battlefield tapped, then shuffle.
Learn. (You may reveal a Lesson card you own from outside the game and put it into your hand, or discard a card to draw a card.)

Expanded Anatomy

Put two +1/+1 counters on target creature. It gains vigilance until end of turn.

Krosan Grip

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Destroy target artifact or enchantment.

Karok Wrangler

Magecraft — Whenever you cast or copy an instant or sorcery spell, put a +1/+1 counter on target creature you control.

Wizard Class

(Gain the next level as a sorcery to add its ability.)
You have no maximum hand size.
{2}{U}: Level 2
When this Class becomes level 2, draw two cards.
{4}{U}: Level 3
Whenever you draw a card, put a +1/+1 counter on target creature you control.

Sagittars' Volley

Destroy target creature with flying. Sagittars' Volley deals 1 damage to each creature with flying your opponents control.

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Immaculate Magistrate

{T}: Put a +1/+1 counter on target creature for each Elf you control.

Frost Trickster

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

Curate

Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
Draw a card.

Snakeskin Veil

Put a +1/+1 counter on target creature you control. It gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

End-Raze Forerunners

Vigilance, trample, haste
When End-Raze Forerunners enters, other creatures you control get +2/+2 and gain vigilance and trample until end of turn.

Dreamroot Cascade

Dreamroot Cascade enters tapped unless you control two or more other lands.
{T}: Add {G} or {U}.

King Harald's Revenge

Until end of turn, target creature gets +1/+1 for each creature you control and gains trample. It must be blocked this turn if able.

Accomplished Alchemist

{T}: Add one mana of any color.
{T}: Add X mana of any one color, where X is the amount of life you gained this turn.

Tanazir Quandrix

Flying, trample
When Tanazir Quandrix enters, double the number of +1/+1 counters on target creature you control.
Whenever Tanazir Quandrix attacks, you may have the base power and toughness of other creatures you control become equal to Tanazir Quandrix's power and toughness until end of turn.

Mercurial Transformation

Until end of turn, target nonland permanent loses all abilities and becomes your choice of a blue Frog creature with base power and toughness 1/1 or a blue Octopus creature with base power and toughness 4/4.

Quandrix Pledgemage

Magecraft — Whenever you cast or copy an instant or sorcery spell, put a +1/+1 counter on Quandrix Pledgemage.

Horizon Seeker

Boast — {1}{G}: Search your library for a basic land card, reveal it, put it into your hand, then shuffle. (Activate only if this creature attacked this turn and only once each turn.)

Shortcut to Mushrooms

When Shortcut to Mushrooms enters, the Ring tempts you.
At the beginning of your end step, if a permanent you controlled left the battlefield this turn, put a +1/+1 counter on target creature you control.

The Ozolith

Whenever a creature you control leaves the battlefield, if it had counters on it, put those counters on The Ozolith.
At the beginning of combat on your turn, if The Ozolith has counters on it, you may move all counters from The Ozolith onto target creature.

Island

In Search of Greatness

At the beginning of your upkeep, you may cast a permanent spell from your hand with mana value equal to 1 plus the highest mana value among other permanents you control without paying its mana cost. If you don't, scry 1.

Triskaidekaphile

You have no maximum hand size.
At the beginning of your upkeep, if you have exactly thirteen cards in your hand, you win the game.
{3}{U}: Draw a card.

Miscast

Counter target instant or sorcery spell unless its controller pays {3}.

Okina, Temple to the Grandfathers

{T}: Add {G}.
{G}, {T}: Target legendary creature gets +1/+1 until end of turn.

Quirion Dryad

Whenever you cast a spell that's white, blue, black, or red, put a +1/+1 counter on Quirion Dryad.

Blessing of Frost

Distribute X +1/+1 counters among any number of creatures you control, where X is the amount of {S} spent to cast this spell. Then draw a card for each creature you control with power 4 or greater.

Dragonsguard Elite

Magecraft — Whenever you cast or copy an instant or sorcery spell, put a +1/+1 counter on Dragonsguard Elite.
{4}{G}{G}: Double the number of +1/+1 counters on Dragonsguard Elite.

Environmental Sciences

Search your library for a basic land card, reveal it, put it into your hand, then shuffle. You gain 2 life.

Primal Plasma

As Primal Plasma enters, it becomes your choice of a 3/3 creature, a 2/2 creature with flying, or a 1/6 creature with defender.

Biomathematician

When Biomathematician enters, create a 0/0 green and blue Fractal creature token. Put a +1/+1 counter on each Fractal you control.

Needlethorn Drake

Square Up

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

Latchkey Faerie

Flying
Prowl {2}{U} (You may cast this for its prowl cost if you dealt combat damage to a player this turn with a Faerie or Rogue.)
When Latchkey Faerie enters, if its prowl cost was paid, draw a card.

Fractal Summoning

Create a 0/0 green and blue Fractal creature token. Put X +1/+1 counters on it.

Command Tower

Boreal Outrider

Whenever you cast a creature spell, if {S} of any of that spell's colors was spent to cast it, that creature enters with an additional +1/+1 counter on it. ({S} is mana from a snow source.)

Tuskguard Captain

Outlast {G} ({G}, {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 trample.