Repulsive Mutation

Put X +1/+1 counters on target creature you control. Then counter up to one target spell unless its controller pays mana equal to the greatest power among creatures you control.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Druid Class

(Gain the next level as a sorcery to add its ability.)
Landfall — Whenever a land enters the battlefield under your control, you gain 1 life.
{2}{G}: Level 2
You may play an additional land on each of your turns.
{4}{G}: Level 3
When this Class becomes level 3, target land you control becomes a creature with haste and "This creature's power and toughness are each equal to the number of lands you control." It's still a land.

Reasonable Doubt

Counter target spell unless its controller pays {2}.
Suspect up to one target creature. (A suspected creature has menace and can't block.)

Simic Growth Chamber

Simic Growth Chamber enters the battlefield tapped.
When Simic Growth Chamber enters the battlefield, return a land you control to its owner's hand.
{T}: Add {G}{U}.

Simic Signet

Llanowar Elves

Glissa Sunslayer

First strike, deathtouch
Whenever Glissa Sunslayer deals combat damage to a player, choose one —
• You draw a card and you lose 1 life.
• Destroy target enchantment.
• Remove up to three counters from target permanent.

Zopandrel, Hunger Dominus

Reach
At the beginning of each combat, double the power and toughness of each creature you control until end of turn.
{G/P}{G/P}, Sacrifice two other creatures: Put an indestructible counter on Zopandrel, Hunger Dominus. ({G/P} can be paid with either {G} or 2 life.)

Vineglimmer Snarl

As Vineglimmer Snarl enters the battlefield, you may reveal a Forest or Island card from your hand. If you don't, Vineglimmer Snarl enters the battlefield tapped.
{T}: Add {G} or {U}.

Root Snare

Prevent all combat damage that would be dealt this turn.

Combat Research

Enchant creature
Enchanted creature has "Whenever this creature deals combat damage to a player, draw a card."
As long as enchanted creature is legendary, it gets +1/+1 and has ward {1}. (Whenever enchanted creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)

Restless Vinestalk

Restless Vinestalk enters the battlefield tapped.
{T}: Add {G} or {U}.
{3}{G}{U}: Until end of turn, Restless Vinestalk becomes a 5/5 green and blue Plant creature with trample. It's still a land.
Whenever Restless Vinestalk attacks, up to one other target creature has base power and toughness 3/3 until end of turn.

Murder

Boseiju, Who Endures

{T}: Add {G}.
Channel — {1}{G}, Discard Boseiju, Who Endures: Destroy target artifact, enchantment, or nonbasic land an opponent controls. That player may search their library for a land card with a basic land type, put it onto the battlefield, then shuffle. This ability costs {1} less to activate for each legendary creature you control.

Bojuka Bog

Bojuka Bog enters the battlefield tapped.
When Bojuka Bog enters the battlefield, exile target player's graveyard.
{T}: Add {B}.

Lush Oasis

Lush Oasis enters the battlefield tapped.
When Lush Oasis enters the battlefield, it deals 1 damage to target opponent.
{T}: Add {G} or {U}.

Tail the Suspect

Investigate. You may play an additional land this turn. (Then exile this card. You may cast the creature later from exile.)

Kellan, Inquisitive Prodigy

Flying, vigilance
Whenever Kellan, Inquisitive Prodigy attacks, destroy up to one target artifact. If you controlled that permanent, draw a card.

Kellan, Inquisitive Prodigy // Tail the Suspect

Sunken Hollow

({T}: Add {U} or {B}.)
Sunken Hollow enters the battlefield tapped unless you control two or more basic lands.

Swamp

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Cazur, Ruthless Stalker

Partner with Ukkima, Stalking Shadow (When this creature enters the battlefield, target player may put Ukkima into their hand from their library, then shuffle.)
Whenever a creature you control deals combat damage to a player, put a +1/+1 counter on that creature.

Woodland Stream

Woodland Stream enters the battlefield tapped.
{T}: Add {G} or {U}.

Druid of the Cowl

Arcane Signet

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

Forced Adaptation

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

Voidslime

Counter target spell, activated ability, or triggered ability. (Mana abilities can't be targeted.)

Champion's Helm

Equipped creature gets +2/+2.
As long as equipped creature is legendary, it has hexproof. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Rishkar, Peema Renegade

When Rishkar, Peema Renegade enters the battlefield, put a +1/+1 counter on each of up to two target creatures.
Each creature you control with a counter on it has "{T}: Add {G}."

Sol Ring

Hullbreaker Horror

Flash
This spell can't be countered.
Whenever you cast a spell, choose up to one —
• Return target spell you don't control to its owner's hand.
• Return target nonland permanent to its owner's hand.

Essence Capture

Counter target creature spell. Put a +1/+1 counter on up to one target creature you control.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Overflowing Basin

As Foretold

At the beginning of your upkeep, put a time counter on As Foretold.
Once each turn, you may pay {0} rather than pay the mana cost for a spell you cast with mana value X or less, where X is the number of time counters on As Foretold.

Leyline of Lifeforce

If Leyline of Lifeforce is in your opening hand, you may begin the game with it on the battlefield.
Creature spells can't be countered.

Island

Thought Vessel

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

Putrefy

Destroy target artifact or creature. It can't be regenerated.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Jungle Hollow

Jungle Hollow enters the battlefield tapped.
When Jungle Hollow enters the battlefield, you gain 1 life.
{T}: Add {B} or {G}.

Thornwood Falls

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

Case of the Locked Hothouse

You may play an additional land on each of your turns.
To solve — You control seven or more lands. (If unsolved, solve at the beginning of your end step.)
Solved — You may look at the top card of your library any time, and you may play lands and cast creature and enchantment spells from the top of your library.

Badlands Revival

Return up to one target creature card from your graveyard to the battlefield. Return up to one target permanent card from your graveyard to your hand.

Spark Double

You may have Spark Double enter the battlefield as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Carpet of Flowers

At the beginning of each of your main phases, if you haven't added mana with this ability this turn, you may add X mana of any one color, where X is the number of Islands target opponent controls.

Path of Ancestry

Path of Ancestry enters the battlefield tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Make Your Own Luck

Look at the top three cards of your library. You may exile a nonland card from among them. If you do, it becomes plotted. Put the rest into your hand. (You may cast it as a sorcery on a later turn without paying its mana cost.)

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}

Tangled Vale

Tangled Vale enters the battlefield tapped.
{T}: Add {G}.

Tangled Florahedron

Tangled Florahedron // Tangled Vale

Hive of the Eye Tyrant

If you control two or more other lands, Hive of the Eye Tyrant enters the battlefield tapped.
{T}: Add {B}.
{3}{B}: Until end of turn, Hive of the Eye Tyrant becomes a 3/3 black Beholder creature with menace and "Whenever this creature attacks, exile target card from defending player's graveyard." It's still a land.

Unnatural Growth

At the beginning of each combat, double the power and toughness of each creature you control until end of turn.

Teferi's Time Twist

Exile target permanent you control. Return that card to the battlefield under its owner's control at the beginning of the next end step. If it enters the battlefield as a creature, it enters with an additional +1/+1 counter on it.

Quirion Beastcaller

Whenever you cast a creature spell, put a +1/+1 counter on Quirion Beastcaller.
When Quirion Beastcaller dies, distribute X +1/+1 counters among any number of target creatures you control, where X is the number of +1/+1 counters on Quirion Beastcaller.

Explosive Vegetation

Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Glen Elendra Liege

Flying
Other blue creatures you control get +1/+1.
Other black creatures you control get +1/+1.

Abrupt Decay

This spell can't be countered.
Destroy target nonland permanent with mana value 3 or less.

Necroblossom Snarl

As Necroblossom Snarl enters the battlefield, you may reveal a Swamp or Forest card from your hand. If you don't, Necroblossom Snarl enters the battlefield tapped.
{T}: Add {B} or {G}.

Gretchen Titchwillow

{2}{G}{U}: Draw a card. You may put a land card from your hand onto the battlefield.

Squirming Emergence

Fathomless descent — Return to the battlefield target nonland permanent card in your graveyard with mana value less than or equal to the number of permanent cards in your graveyard.

Lost Jitte

Whenever equipped creature deals combat damage, put a charge counter on Lost Jitte.
Remove a charge counter from Lost Jitte: Choose one —
• Untap target land.
• Target creature can't block this turn.
• Put a +1/+1 counter on equipped creature.
Equip {1}

Commencement of Festivities

Prevent all combat damage that would be dealt to players this turn.

Negate

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

In Garruk's Wake

Destroy all creatures you don't control and all planeswalkers you don't control.

Forest

Command Tower

Rakshasa's Disdain

Counter target spell unless its controller pays {1} for each card in your graveyard.

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Sylvan Scrying

Search your library for a land card, reveal it, put it into your hand, then shuffle.

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Explore

You may play an additional land this turn.
Draw a card.

Rimewood Falls

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

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Dark Ritual

Golgari Signet

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.)

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.)

Hedge Maze

({T}: Add {G} or {U}.)
Hedge Maze enters the battlefield tapped.
When Hedge Maze enters the battlefield, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Luxior, Giada's Gift

Equipped creature gets +1/+1 for each counter on it.
Equipped permanent isn't a planeswalker and is a creature in addition to its other types. (Loyalty abilities can still be activated.)
Equip planeswalker {1}
Equip {3}

Talisman of Curiosity

{T}: Add {C}.
{T}: Add {G} or {U}. Talisman of Curiosity deals 1 damage to you.

Temple of Mystery

Temple of Mystery enters the battlefield tapped.
When Temple of Mystery enters the battlefield, scry 1.
{T}: Add {G} or {U}.

Ukkima, Stalking Shadow

Partner with Cazur, Ruthless Stalker (When this creature enters the battlefield, target player may put Cazur into their hand from their library, then shuffle.)
Ukkima, Stalking Shadow can't be blocked.
When Ukkima leaves the battlefield, it deals X damage to target player and you gain X life, where X is its power.

Countervailing Winds

Counter target spell unless its controller pays {1} for each card in your graveyard.
Cycling {2} ({2}, Discard this card: Draw a card.)

Hulking Raptor

Ward {2}
At the beginning of your precombat main phase, add {G}{G}.

Slitherhead

Scavenge {0} ({0}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)