Once Upon a Time

If this spell is the first spell you've cast this game, you may cast it without paying its mana cost.
Look at the top five cards of your library. You may reveal a creature or land card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Plateau

Vault 21: House Gambit

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Discard a card, then draw a card.
III — Reveal up to five nonland cards from your hand. For each of those cards that has the same mana value as another card revealed this way, create a Treasure token.

Magus of the Moon

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

City of Traitors

When you play another land, sacrifice City of Traitors.
{T}: Add {C}{C}.

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Sibylline Soothsayer

Temporal Foresight — When Sibylline Soothsayer enters, reveal cards from the top of your library until you reveal a nonland card with mana value 3 or greater. Exile that card with three time counters on it. If it doesn't have suspend, it gains suspend. Put the rest of the revealed cards on the bottom of your library in a random order.

Overencumbered

Enchant opponent
When Overencumbered enters, enchanted opponent creates a Clue token, a Food token, and a Junk token.
At the beginning of combat on enchanted opponent's turn, that player may pay {1} for each artifact they control. If they don't, creatures can't attack this combat.

Ancient Tomb

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Forth Eorlingas!

Create X 2/2 red Human Knight creature tokens with trample and haste.
Whenever one or more creatures you control deal combat damage to one or more players this turn, you become the monarch.

Ethersworn Canonist

Each player who has cast a nonartifact spell this turn can't cast additional nonartifact spells.

Cavern of Souls

As Cavern of Souls enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

Dinosaurs on a Spaceship

Vigilance, trample
Other Dinosaurs you control get +1/+1 and have vigilance and trample.
Suspend 4—{3}{R}{W}
Whenever a time counter is removed from Dinosaurs on a Spaceship while it's exiled, create a 2/2 red and white Dinosaur creature token with flying and haste.

Chalice of the Void

Chalice of the Void enters with X charge counters on it.
Whenever a player casts a spell with mana value equal to the number of charge counters on Chalice of the Void, counter that spell.

Containment Priest

Flash
If a nontoken creature would enter and it wasn't cast, exile it instead.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Taiga

Inti, Seneschal of the Sun

Whenever you attack, you may discard a card. When you do, put a +1/+1 counter on target attacking creature. It gains trample until end of turn.
Whenever you discard one or more cards, exile the top card of your library. You may play that card until your next end step.

Caves of Chaos Adventurer

Trample
When Caves of Chaos Adventurer enters, you take the initiative.
Whenever Caves of Chaos Adventurer attacks, exile the top card of your library. If you've completed a dungeon, you may play that card this turn without paying its mana cost. Otherwise, you may play that card this turn.

Plains

Mountain

Unyielding Gatekeeper

Disguise {1}{W} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)
When Unyielding Gatekeeper is turned face up, exile another target nonland permanent. If you controlled it, return it to the battlefield tapped. Otherwise, its controller creates a 2/2 white and blue Detective creature token.

Null Rod

Activated abilities of artifacts can't be activated.

Seek the Beast

Exile the top two cards of your library. Until your next end step, you may play those cards.

Questing Druid

Whenever you cast a spell that's white, blue, black, or red, put a +1/+1 counter on Questing Druid.

Questing Druid // Seek the Beast

Unlicensed Hearse

{T}: Exile up to two target cards from a single graveyard.
Unlicensed Hearse's power and toughness are each equal to the number of cards exiled with it.
Crew 2

Chrome Mox

Imprint — When Chrome Mox enters, you may exile a nonartifact, nonland card from your hand.
{T}: Add one mana of any of the exiled card's colors.