Rottenmouth Viper

As an additional cost to cast this spell, you may sacrifice any number of nonland permanents. This spell costs {1} less to cast for each permanent sacrificed this way.
Whenever Rottenmouth Viper enters or attacks, put a blight counter on it. Then for each blight counter on it, each opponent loses 4 life unless that player sacrifices a nonland permanent or discards a card.

Overgrown Tomb

({T}: Add {B} or {G}.)
As Overgrown Tomb enters, you may pay 2 life. If you don't, it enters tapped.

Gruff Triplets

Trample
When Gruff Triplets enters, if it isn't a token, create two tokens that are copies of it.
When Gruff Triplets dies, put a number of +1/+1 counters equal to its power on each creature you control named Gruff Triplets.

Scurry Oak

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever one or more +1/+1 counters are put on Scurry Oak, you may create a 1/1 green Squirrel creature token.

Dreamtide Whale

Vanishing 2 (This creature enters with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a player casts their second spell each turn, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Beast Within

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

Mirkwood Bats

Flying
Whenever you create or sacrifice a token, each opponent loses 1 life.

Worldly Tutor

Search your library for a creature card, reveal it, then shuffle and put the card on top.

Innkeeper's Talent

(Gain the next level as a sorcery to add its ability.)
At the beginning of combat on your turn, put a +1/+1 counter on target creature you control.
{G}: Level 2
Permanents you control with counters on them have ward {1}.
{3}{G}: Level 3
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.

Thrummingbird

Flying
Whenever Thrummingbird deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Gift of the Viper

Put a +1/+1 counter, a reach counter, and a deathtouch counter on target creature. Untap it.

Birds of Paradise

Gyre Sage

Evolve (Whenever a creature you control enters, 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.

Tendershoot Dryad

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
At the beginning of each upkeep, create a 1/1 green Saproling creature token.
Saprolings you control get +2/+2 as long as you have the city's blessing.

The Great Henge

This spell costs {X} less to cast, where X is the greatest power among creatures you control.
{T}: Add {G}{G}. You gain 2 life.
Whenever a nontoken creature you control enters, put a +1/+1 counter on it and draw a card.

Basking Broodscale

Devoid (This card has no color.)
{1}{G}: 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 Basking Broodscale, you may create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this creature: Add {C}."

Watery Grave

({T}: Add {U} or {B}.)
As Watery Grave enters, you may pay 2 life. If you don't, it enters tapped.

Intruder Alarm

Creatures don't untap during their controllers' untap steps.
Whenever a creature enters, untap all creatures.

Karn's Bastion

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Evolution Sage

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

Xavier Sal, Infested Captain

{T}, Remove a counter from another permanent you control: Populate. Activate only as a sorcery. (Create a token that's a copy of a creature token you control.)
{T}, Sacrifice another creature: Proliferate. Activate only as a sorcery. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Swamp

Octomancer

Gift an Octopus (You may promise an opponent a gift as you cast this spell. If you do, when it enters, they create an 8/8 blue Octopus creature token.)
At the beginning of each end step, create a token that's a copy of target creature token that entered the battlefield this turn.

Atomize

Destroy target nonland permanent. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Deadly Rollick

If you control a commander, you may cast this spell without paying its mana cost.
Exile target creature.

Rogue's Passage

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

Foreboding Landscape

{T}: Add {C}.
{T}, Sacrifice Foreboding Landscape: Search your library for a basic Swamp, Forest, or Island card, put it onto the battlefield tapped, then shuffle.
Cycling {B}{G}{U} ({B}{G}{U}, Discard this card: Draw a card.)

Fathom Mage

Evolve (Whenever a creature you control enters, 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.

Zagoth Triome

({T}: Add {B}, {G}, or {U}.)
Zagoth Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Three Visits

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

Corpsejack Menace

If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on it instead.

Nature's Lore

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

Replicating Ring

{T}: Add one mana of any color.
At the beginning of your upkeep, put a night counter on Replicating Ring. Then if it has eight or more night counters on it, remove all of them and create eight colorless snow artifact tokens named Replicated Ring with "{T}: Add one mana of any color."

Mycoloth

Devour 2 (As this enters, you may sacrifice any number of creatures. This creature enters with twice that many +1/+1 counters on it.)
At the beginning of your upkeep, create a 1/1 green Saproling creature token for each +1/+1 counter on Mycoloth.

Breeding Pool

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

Ripples of Potential

Proliferate, then choose any number of permanents you control that had a counter put on them this way. Those permanents phase out. (To proliferate, choose any number of permanents and/or players, then give each another counter of each kind already there. Treat phased-out permanents and anything attached to them as though they don't exist until their controller's next turn.)

Prologue to Phyresis

Each opponent gets a poison counter.
Draw a card.

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Mutational Advantage

Permanents you control with counters on them gain hexproof and indestructible until end of turn. Prevent all damage that would be dealt to those permanents this turn. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Morphic Pool

Morphic Pool enters tapped unless you have two or more opponents.
{T}: Add {U} or {B}.

Rootcast Apprenticeship

Choose three. You may choose the same mode more than once.
• Put two +1/+1 counters on target creature.
• Create a token that's a copy of target token you control.
• Target player creates a 1/1 green Squirrel creature token.
• Target opponent sacrifices a nontoken artifact.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Vraska, Betrayal's Sting

Compleated ({B/P} can be paid with {B} or 2 life. If life was paid, this planeswalker enters with two fewer loyalty counters.)
0: You draw a card and you lose 1 life. Proliferate.
−2: Target creature becomes a Treasure artifact with "{T}, Sacrifice this artifact: Add one mana of any color" and loses all other card types and abilities.
−9: If target player has fewer than nine poison counters, they get a number of poison counters equal to the difference.

Vraska's Fall

Each opponent sacrifices a creature or planeswalker and gets a poison counter.

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.

Bloated Contaminator

Trample
Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Whenever Bloated Contaminator deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Nemata, Primeval Warden

Reach
If a creature an opponent controls would die, exile it instead. When you do, create a 1/1 green Saproling creature token.
{G}, Sacrifice a Saproling: Nemata, Primeval Warden gets +2/+2 until end of turn.
{1}{B}, Sacrifice two Saprolings: Draw a card.

Bloodroot Apothecary

Toxic 2 (Players dealt combat damage by this creature also get two poison counters. A player with ten or more poison counters loses the game.)
When Bloodroot Apothecary enters, you and target opponent each create a Treasure token.
Whenever an opponent sacrifices a noncreature token, that player gets two poison counters.

Island

Opulent Palace

Opulent Palace enters tapped.
{T}: Add {B}, {G}, or {U}.

Kiora's Follower

Hinterland Harbor

Hinterland Harbor enters tapped unless you control a Forest or an Island.
{T}: Add {G} or {U}.

Tekuthal, Inquiry Dominus

Flying
If you would proliferate, proliferate twice instead.
{1}{U/P}{U/P}, Remove three counters from among other artifacts, creatures, and planeswalkers you control: Put an indestructible counter on Tekuthal, Inquiry Dominus. ({U/P} can be paid with either {U} or 2 life.)

Command Tower

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

Undergrowth Stadium

Undergrowth Stadium enters tapped unless you have two or more opponents.
{T}: Add {B} or {G}.

Kami of Whispered Hopes

If one or more +1/+1 counters would be put on a permanent you control, that many plus one +1/+1 counters are put on that permanent instead.
{T}: Add X mana of any one color, where X is Kami of Whispered Hopes's power.

Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Rampant Growth

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

Master Biomancer

Each other creature you control enters 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.

Winding Constrictor

If one or more counters would be put on an artifact or creature you control, that many plus one of each of those kinds of counters are put on that permanent instead.
If you would get one or more counters, you get that many plus one of each of those kinds of counters instead.

Doubling Season

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

Watchful Radstag

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever Watchful Radstag evolves, create a token that's a copy of it.

Tender Wildguide

Offspring {2} (You may pay an additional {2} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
{T}: Add one mana of any color.
{T}: Put a +1/+1 counter on this creature.

Deepglow Skate

When Deepglow Skate enters, double the number of each kind of counter on any number of target permanents.

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.

Sol Ring

Damnation

Destroy all creatures. They can't be regenerated.

Tainted Observer

Flying
Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Whenever another creature you control enters, you may pay {2}. If you do, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Tyvar, Jubilant Brawler

You may activate abilities of creatures you control as though those creatures had haste.
+1: Untap up to one target creature.
−2: Mill three cards, then you may return a creature card with mana value 2 or less from your graveyard to the battlefield.

Tezzeret's Gambit

({U/P} can be paid with either {U} or 2 life.)
Draw two cards, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Farseek

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

Forest

Rejuvenating Springs

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

Reef Worm

When Reef Worm dies, create a 3/3 blue Fish creature token with "When this creature dies, create a 6/6 blue Whale creature token with 'When this creature dies, create a 9/9 blue Kraken creature token.'"

Ezuri, Stalker of Spheres

When Ezuri, Stalker of Spheres enters, you may pay {3}. If you do, proliferate twice.
Whenever you proliferate, draw a card.

Managorger Hydra

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

Arcane Signet

Adrix and Nev, Twincasters

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
If one or more tokens would be created under your control, twice that many of those tokens are created instead.

Agent Frank Horrigan

Trample
Agent Frank Horrigan has indestructible as long as it attacked this turn.
Whenever Agent Frank Horrigan enters or attacks, proliferate twice. (To proliferate, choose any number of permanents and/or players, then give each another counter of each kind already there.)

Evolution Witness

{1}{G}: Adapt 2. (If this creature has no +1/+1 counters on it, put two +1/+1 counters on it.)
Whenever one or more +1/+1 counters are put on Evolution Witness, return target permanent card from your graveyard to your hand.