Temple of Mystery

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

Lumbering Megasloth

This spell costs {1} less to cast for each counter among players and permanents.
Trample
Lumbering Megasloth enters tapped.

Tireless Tracker

Landfall — Whenever a land you control enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Whenever you sacrifice a Clue, put a +1/+1 counter on Tireless Tracker.

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 Nightkin Ambusher enters, target player gets four rad counters.
Nightkin Ambusher can't be blocked as long as defending player has a rad counter.

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.

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.

Mariposa Military Base

You may have Mariposa Military Base 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.

Mirelurk Queen

Vigilance
When Mirelurk Queen 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 Mirelurk Queen. This ability triggers only once each turn.

Tainted Isle

{T}: Add {C}.
{T}: Add {U} or {B}. Activate only if you control a Swamp.

Evolving Wilds

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

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.

Harold and Bob, First Numens

Vigilance, reach
When Harold and Bob, First Numens 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.

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.)

Contagion Clasp

When Contagion Clasp 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.)

Radstorm

Storm (When you cast this spell, copy it for each spell cast before it this turn.)
Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Screeching Scorchbeast

Flying, menace
Whenever Screeching Scorchbeast 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.

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.)

Vault 87: Forced Evolution

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Gain control of target non-Mutant creature for as long as you control Vault 87.
II — Put a +1/+1 counter on target creature you control. It becomes a Mutant in addition to its other types.
III — Draw cards equal to the greatest power among Mutants you control.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

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.

Arcane Signet

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

Swamp

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}

Struggle for Project Purity

As Struggle for Project Purity 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.

Exotic Orchard

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

Sunken Hollow

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

Darkwater Catacombs

Viridescent Bog

Putrefy

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

Nesting Grounds

{T}: Add {C}.
{1}, {T}: Move a counter from target permanent you control onto another target permanent. Activate only as a sorcery.

Piper Wright, Publick Reporter

Whenever Piper Wright deals combat damage to a player, investigate that many times. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Whenever you sacrifice a Clue, put a +1/+1 counter on target creature you control.

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.

Rampant Growth

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

The Master, Transcendent

When The Master, Transcendent 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.)

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.

Strength Bobblehead

{T}: Add one mana of any color.
{3}, {T}: Put X +1/+1 counters on target creature, where X is the number of Bobbleheads you control. Activate only as a sorcery.

Biomass Mutation

Creatures you control have base power and toughness X/X until end of turn.

Contaminated Drink

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

Inexorable Tide

Whenever you cast a spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Power Fist

Equipped creature has trample and "Whenever this creature deals combat damage to a player, put that many +1/+1 counters on it."
Equip {2}

Recon Craft Theta

Flying
When Recon Craft Theta enters, create a 0/0 blue Alien creature token. Put a +1/+1 counter on it.
Whenever Recon Craft Theta attacks, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Crew 2

Ash Barrens

{T}: Add {C}.
Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

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.

Sol Ring

Bloatfly Swarm

Flying
Bloatfly Swarm enters with five +1/+1 counters on it.
If damage would be dealt to Bloatfly Swarm 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.

Island

Jason Bright, Glowing Prophet

Whenever a Zombie or Mutant you control dies, if its power was different from its base power, draw a card.
Come Fly With Me — {2}, Sacrifice a creature: Put a +1/+1 counter on target creature you control. It gains flying until end of turn.

Command Tower

Feral Ghoul

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

Lily Bowen, Raging Grandma

Vigilance
Lily Bowen, Raging Grandma enters with two +1/+1 counters on it.
At the beginning of your upkeep, double the number of +1/+1 counters on Lily Bowen if its power is 16 or less. Otherwise, remove all but one +1/+1 counter from it, then you gain 1 life for each +1/+1 counter removed this way.

Overflowing Basin

Terramorphic Expanse

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

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.

Talisman of Resilience

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

Glowing One

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

Tainted Wood

{T}: Add {C}.
{T}: Add {B} or {G}. Activate only if you control a Swamp.

Vexing Radgull

Flying
Whenever Vexing Radgull 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.)

Marcus, Mutant Mayor

Vigilance, trample
Whenever a creature you control deals combat damage to a player, draw a card if that creature has a +1/+1 counter on it. If it doesn't, put a +1/+1 counter on it.

Hancock, Ghoulish Mayor

Each other creature you control that's a Zombie or Mutant gets +X/+X, where X is the number of counters on Hancock, Ghoulish Mayor.
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

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.

Nuclear Fallout

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

Talisman of Dominance

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

Farseek

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

Woodland Cemetery

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

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.

Harmonize

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.

Rampaging Yao Guai

Vigilance, trample
Rampaging Yao Guai enters with X +1/+1 counters on it.
When Rampaging Yao Guai enters, destroy any number of target artifacts and/or enchantments with total mana value X or less.

Talisman of Curiosity

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

Atomize

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

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.)

Temple of Deceit

Temple of Deceit enters tapped.
When Temple of Deceit enters, scry 1.
{T}: Add {U} or {B}.

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.

Raul, Trouble Shooter

Once during each of your turns, you may cast a spell from among cards in your graveyard that were milled this turn.
{T}: Each player mills a card. (They each put the top card of their library into their graveyard.)

Hinterland Harbor

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

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.

Young Deathclaws

Menace (This creature can't be blocked except by two or more creatures.)
Each creature card in your graveyard has scavenge. The scavenge cost is equal to its mana cost. (Exile a creature card from your graveyard and pay its mana cost: Put a number of +1/+1 counters equal to that card's power on target creature. Scavenge only as a sorcery.)

Forest

Mortuary Mire

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

Path of Ancestry

Path of Ancestry enters 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.)

Temple of Malady

Temple of Malady enters tapped.
When Temple of Malady enters, scry 1.
{T}: Add {B} or {G}.

Infesting Radroach

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

Fetid Pools

({T}: Add {U} or {B}.)
Fetid Pools enters tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

Alpha Deathclaw

Menace, trample
When Alpha Deathclaw 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.)

Casualties of War

Choose one or more —
• Destroy target artifact.
• Destroy target creature.
• Destroy target enchantment.
• Destroy target land.
• Destroy target planeswalker.

Drowned Catacomb

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

Finality

You may put two +1/+1 counters on a creature you control. Then all creatures get -4/-4 until end of turn.