Underground River

{T}: Add {C}.
{T}: Add {U} or {B}. This land deals 1 damage to you.

Court of Cunning

When this enchantment enters, you become the monarch.
At the beginning of your upkeep, any number of target players each mill two cards. If you're the monarch, each of those players mills ten cards instead. (To mill a card, a player puts the top card of their library into their graveyard.)

Bloated Contaminator

Trample
Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Whenever this creature 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.)

Icetill Explorer

You may play an additional land on each of your turns.
You may play lands from your graveyard.
Landfall — Whenever a land you control enters, mill a card.

Naturalize

Sol Ring

Maelstrom Pulse

Destroy target nonland permanent and all other permanents with the same name as that permanent.

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

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.

Forge of Heroes

{T}: Add {C}.
{T}: Choose target commander that entered this turn. Put a +1/+1 counter on it if it's a creature and a loyalty counter on it if it's a planeswalker.

Guardian Project

Whenever a nontoken creature you control enters, if it doesn't have the same name as another creature you control or a creature card in your graveyard, draw a card.

Forest

Alpha Deathclaw

Menace, trample
When this creature enters or becomes monstrous, destroy target permanent.
{5}{B}{G}: Monstrosity 4. (If this creature isn't monstrous, put four +1/+1 counters on it and it becomes monstrous.)

Contagion Engine

When this artifact enters, put a -1/-1 counter on each creature target player controls.
{4}, {T}: Proliferate twice. (Choose any number of permanents and/or players, then give each another counter of each kind already there. Then do it again.)

Beast Within

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

Woodland Cemetery

This land enters tapped unless you control a Swamp or a Forest.
{T}: Add {B} or {G}.

Cathedral Acolyte

Each creature you control with a counter on it has ward {1}. (Whenever it becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)
{T}: Put a +1/+1 counter on target creature that entered this turn.

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.)

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.)

Putrefy

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

Emry, Lurker of the Loch

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
When Emry enters, mill four cards.
{T}: Choose target artifact card in your graveyard. You may cast that card this turn. (You still pay its costs. Timing rules still apply.)

Cankerbloom

{1}, Sacrifice this creature: Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Swamp

Windgrace's Judgment

For any number of opponents, destroy target nonland permanent that player controls.

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 this creature, you may create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this token: Add {C}."

The Water Crystal

Blue spells you cast cost {1} less to cast.
If an opponent would mill one or more cards, they mill that many cards plus four instead.
{4}{U}{U}, {T}: Each opponent mills cards equal to the number of cards in your hand.

Feral Ghoul

Menace
Whenever another creature you control dies, put a +1/+1 counter on this creature.
When this creature dies, each opponent gets a number of rad counters equal to its power.

Field of Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice this land: Destroy target nonbasic land an opponent controls. Each player searches their library for a basic land card, puts it onto the battlefield, then shuffles.

Vault 12: The Necropolis

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Each player gets three rad counters.
II — Create X 2/2 black Zombie Mutant creature tokens, where X is the total number of rad counters among players.
III — Put two +1/+1 counters on each creature you control that's a Zombie or Mutant.

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 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.

Nuka-Nuke Launcher

Equipped creature gets +3/+0 and has intimidate. (It can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Whenever equipped creature attacks, until the end of defending player's next turn, that player gets two rad counters whenever they cast a spell.
Equip {3}

Mirelurk Queen

Vigilance
When this creature enters, target player gets two rad counters.
Whenever one or more nonland cards are milled, draw a card, then put a +1/+1 counter on this creature. This ability triggers only once each turn.

Bruvac the Grandiloquent

If an opponent would mill one or more cards, they mill twice that many cards instead. (To mill a card, a player puts the top card of their library into their graveyard.)

Sunken Hollow

({T}: Add {U} or {B}.)
This land enters tapped unless you control two or more basic lands.

Sculpting Steel

You may have this artifact enter as a copy of any artifact on the battlefield.

Altar of the Brood

Whenever another permanent you control enters, each opponent mills a card.

Mariposa Military Base

You may have this land enter tapped. If you do, you get two rad counters.
{T}: Add {C}.
{5}, {T}: Draw a card. This ability costs {1} less to activate for each rad counter you have.

Drown in Ichor

Target creature gets -4/-4 until end of turn. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Tato Farmer

Landfall — Whenever a land you control enters, you may get two rad counters.
{T}: Put target land card in a graveyard that was milled this turn onto the battlefield under your control tapped.

Terisian Mindbreaker

Whenever this creature attacks, defending player mills half their library, rounded up.
Unearth {1}{U}{U}{U} ({1}{U}{U}{U}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Island

Fraying Sanity

Enchant player
At the beginning of each end step, enchanted player mills X cards, where X is the number of cards put into their graveyard from anywhere this turn.

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 this creature.

Oran-Rief, the Vastwood

This land enters tapped.
{T}: Add {G}.
{T}: Put a +1/+1 counter on each green creature that entered this turn.

Undead Alchemist

If a Zombie you control would deal combat damage to a player, instead that player mills that many cards.
Whenever a creature card is put into an opponent's graveyard from their library, exile that card and create a 2/2 black Zombie creature token.

Nightkin Ambusher

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
When this creature enters, target player gets four rad counters.
This creature can't be blocked as long as defending player has a rad counter.

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.)

Tanglepool Bridge

This land enters tapped.
Indestructible
{T}: Add {G} or {U}.

Didn't Say Please

Counter target spell. Its controller mills three cards.

Return to Nature

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Exile target card from a graveyard.

Unnatural Restoration

Return target permanent card from your graveyard to your hand. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

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. ({U/P} can be paid with either {U} or 2 life.)

Bloatfly Swarm

Flying
This creature enters with five +1/+1 counters on it.
If damage would be dealt to this creature while it has a +1/+1 counter on it, prevent that damage, remove that many +1/+1 counters from it, then give each player a rad counter for each +1/+1 counter removed this way.

Screeching Scorchbeast

Flying, menace
Whenever this creature attacks, each player gets two rad counters.
Whenever one or more nonland cards are milled, you may create that many 2/2 black Zombie Mutant creature tokens. Do this only once each turn.

Breeding Pool

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

Venerated Rotpriest

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Whenever a creature you control becomes the target of a spell, target opponent gets a poison counter.

Watery Grave

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

The Master, Transcendent

When The Master enters, target player gets two rad counters.
{T}: Put target creature card in a graveyard that was milled this turn onto the battlefield under your control. It's a green Mutant with base power and toughness 3/3. (It loses its other colors and creature types.)

Contaminated Drink

Draw X cards, then you get half X rad counters, rounded up.

Arcane Signet

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

Thrummingbird

Flying
Whenever this creature 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.)

Harold and Bob, First Numens

Vigilance, reach
When Harold and Bob dies, if it was a creature, return it to the battlefield. It's an Aura enchantment with enchant Forest you control and "Enchanted Forest has '{T}: Add three mana of any one color. You get two rad counters.'" Harold and Bob loses all other abilities.

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.)

Branching Evolution

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

Vexing Radgull

Flying
Whenever this creature deals combat damage to a player, that player gets two rad counters if they don't have any rad counters. Otherwise, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Buried Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice this land: Return target artifact card from your graveyard to your hand.

Glowing One

Deathtouch
Whenever this creature deals combat damage to a player, they get four rad counters.
Whenever a player mills a nonland card, you gain 1 life.

Drowned Catacomb

This land enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

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 this creature's power.

Bojuka Bog

This land enters tapped.
When this land enters, exile target player's graveyard.
{T}: Add {B}.

The Wise Mothman

Flying
Whenever The Wise Mothman enters or attacks, each player gets a rad counter.
Whenever one or more nonland cards are milled, put a +1/+1 counter on each of up to X target creatures, where X is the number of nonland cards milled this way.

Mortuary Mire

This land enters tapped.
When this land enters, you may put target creature card from your graveyard on top of your library.
{T}: Add {B}.

Hardened Scales

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

Go for the Throat

Consuming Aberration

Consuming Aberration's power and toughness are each equal to the number of cards in your opponents' graveyards.
Whenever you cast a spell, each opponent reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard.

Swarmyard

{T}: Add {C}.
{T}: Regenerate target Insect, Rat, Spider, or Squirrel. (The next time it would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Mindcrank

Whenever an opponent loses life, that player mills that many cards. (Damage causes loss of life.)

Fleet Swallower

Whenever this creature attacks, target player mills half their library, rounded up.

Struggle for Project Purity

As this enchantment enters, choose Brotherhood or Enclave.
• Brotherhood — At the beginning of your upkeep, each opponent draws a card. You draw a card for each card drawn this way.
• Enclave — Whenever a player attacks you with one or more creatures, that player gets twice that many rad counters.

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.

Nuclear Fallout

Each creature gets twice -X/-X until end of turn. Each player gets X rad counters.

Contagion Clasp

When this artifact enters, put a -1/-1 counter on target creature.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Vault of Whispers

Hedron Crab

Landfall — Whenever a land you control enters, target player mills three cards. (They put the top three cards of their library into their graveyard.)

Mind Grind

Each opponent reveals cards from the top of their library until they reveal X land cards, then puts all cards revealed this way into their graveyard. X can't be 0.

Hinterland Harbor

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

Command Beacon

{T}: Add {C}.
{T}, Sacrifice this land: Put your commander into your hand from the command zone.

Strong, the Brutish Thespian

Ward {2}
Enrage — Whenever Strong is dealt damage, you get three rad counters and put three +1/+1 counters on Strong.
You gain life rather than lose life from radiation.

Atomize

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

Command Tower

Infesting Radroach

Flying
This creature can't block.
Whenever this creature deals combat damage to a player, they get that many rad counters.
Whenever an opponent mills a nonland card, if this creature is in your graveyard, you may return it to your hand.