Mountain

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.)

Walking Ballista

Walking Ballista enters with X +1/+1 counters on it.
{4}: Put a +1/+1 counter on Walking Ballista.
Remove a +1/+1 counter from Walking Ballista: It deals 1 damage to any target.

Brotherhood Outcast

When Brotherhood Outcast enters, choose one —
• Return target Aura or Equipment card with mana value 3 or less from your graveyard to the battlefield.
• Put a shield counter on target creature. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)

Pip-Boy 3000

Whenever equipped creature attacks, choose one —
• Sort Inventory — Draw a card, then discard a card.
• Pick a Perk — Put a +1/+1 counter on that creature.
• Check Map — Untap up to two target lands.
Equip {2}

Megaton's Fate

Choose one —
• Disarm — Destroy target artifact. Create four Treasure tokens.
• Detonate — Megaton's Fate deals 8 damage to each creature. Each player gets four rad counters.

Arcane Signet

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

Sierra, Nuka's Biggest Fan

The Nuka-Cola Challenge — Whenever one or more creatures you control deal combat damage to a player, put a quest counter on Sierra, Nuka's Biggest Fan and create a Food token.
Whenever you sacrifice a Food, target creature you control gets +X/+X until end of turn, where X is the number of quest counters on Sierra.

Overseer of Vault 76

First Contact — Whenever Overseer of Vault 76 or another creature you control with power 3 or less enters, put a quest counter on Overseer of Vault 76.
At the beginning of combat on your turn, you may remove three quest counters from among permanents you control. When you do, put a +1/+1 counter on each creature you control and they gain vigilance until end of turn.

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

Acquired Mutation

Enchant creature
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, defending player gets two rad counters.

Vault 101: Birthday Party

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create a 1/1 white Human Soldier creature token and a Food token. (A Food token is an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
II, III — You may put an Aura or Equipment card from your hand or graveyard onto the battlefield. If an Equipment is put onto the battlefield this way, you may attach it to a creature you control.

Survivor's Med Kit

{1}, {T}: Choose one that hasn't been chosen —
• Stimpak — Draw a card.
• Fancy Lads Snack Cakes — Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
• RadAway — Target player loses all rad counters. Sacrifice Survivor's Med Kit.

Luminarch Ascension

At the beginning of each opponent's end step, if you didn't lose life this turn, you may put a quest counter on Luminarch Ascension. (Damage causes loss of life.)
{1}{W}: Create a 4/4 white Angel creature token with flying. Activate only if Luminarch Ascension has four or more quest counters on it.

Everflowing Chalice

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
Everflowing Chalice enters with a charge counter on it for each time it was kicked.
{T}: Add {C} for each charge counter on Everflowing Chalice.

Duchess, Wayward Tavernkeep

Hunters for Hire — Whenever a creature you control deals combat damage to a player, put a quest counter on it.
{1}, Remove a quest counter from a permanent you control: Create a Junk token. (It's an artifact with "{T}, Sacrifice this artifact: Exile the top card of your library. You may play that card this turn. Activate only as a sorcery.")

Securitron Squadron

Squad {3} (As an additional cost to cast this spell, you may pay {3} any number of times. When this creature enters, create that many tokens that are copies of it.)
Vigilance
Whenever a creature token you control enters, put a +1/+1 counter on it.

Ian the Reckless

Whenever Ian the Reckless attacks, if it's modified, you may have it deal damage equal to its power to you and any target. (Equipment, Auras you control, and counters are modifications.)

C.A.M.P.

Whenever fortified land is tapped for mana, put a +1/+1 counter on target creature you control. If that creature shares a color with the mana that land produced, create a Junk token. (It's an artifact with "{T}, Sacrifice this artifact: Exile the top card of your library. You may play that card this turn. Activate only as a sorcery.")
Fortify {3} ({3}: Attach to target land you control. Fortify only as a sorcery.)

Plains

Sol Ring

Battle of Hoover Dam

As Battle of Hoover Dam enters, choose NCR or Legion.
• NCR — At the beginning of your end step, return target creature card with mana value 3 or less from your graveyard to the battlefield with a finality counter on it.
• Legion — Whenever a creature you control dies, put two +1/+1 counters on target creature you control.

Assemble the Legion

At the beginning of your upkeep, put a muster counter on Assemble the Legion. Then create a 1/1 red and white Soldier creature token with haste for each muster counter on Assemble the Legion.

Nesting Grounds

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

Vault 75: Middle School

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Exile all creatures with power 4 or greater.
II, III — Put a +1/+1 counter on each creature you control.

ED-E, Lonesome Eyebot

Flying
ED-E My Love — Whenever you attack, if the number of attacking creatures is greater than the number of quest counters on ED-E, Lonesome Eyebot, put a quest counter on it.
{2}, Sacrifice ED-E: Draw a card, then draw an additional card for each quest counter on ED-E.

Yes Man, Personal Securitron

{T}: Target opponent gains control of Yes Man, Personal Securitron. When they do, you draw two cards and put a quest counter on Yes Man. Activate only during your turn.
Wild Card — When Yes Man leaves the battlefield, its owner creates a tapped 1/1 white Soldier creature token for each quest counter on it.

Craig Boone, Novac Guard

Reach, lifelink
One for My Baby — Whenever you attack with two or more creatures, put two quest counters on Craig Boone, Novac Guard. When you do, Craig Boone deals damage equal to the number of quest counters on it to up to one target creature unless that creature's controller has Craig Boone deal that much damage to them.

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.

Moira Brown, Guide Author

When Moira Brown, Guide Author enters, create a colorless Equipment artifact token named Wasteland Survival Guide with "Equipped creature gets +1/+1 for each quest counter among permanents you control" and equip {1}.
Whenever you attack, put a quest counter on target nonland permanent you control.

Diamond City

Diamond City enters with a shield counter on it. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)
{T}: Add {C}.
{T}: Move a shield counter from Diamond City onto target creature. Activate only if two or more creatures entered the battlefield under your control this turn.