Volatile Fjord

({T}: Add {U} or {R}.)
Volatile Fjord enters tapped.

Island

Insectile Aberration

Delver of Secrets

At the beginning of your upkeep, look at the top card of your library. You may reveal that card. If an instant or sorcery card is revealed this way, transform Delver of Secrets.

Delver of Secrets // Insectile Aberration

Mountain

Archaeomancer

When Archaeomancer enters, return target instant or sorcery card from your graveyard to your hand.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Counterspell

Thunderous Wrath

Thunderous Wrath deals 5 damage to any target.
Miracle {R} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

Lava Dart

Lava Dart deals 1 damage to any target.
Flashback—Sacrifice a Mountain. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

Bloodwater Entity

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Bloodwater Entity enters, you may put target instant or sorcery card from your graveyard on top of your library.

Molten Tributary

({T}: Add {U} or {R}.)
Molten Tributary enters tapped.

Monastery Swiftspear

Haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Planar Incision

Exile target artifact or creature, then return it to the battlefield under its owner's control with a +1/+1 counter on it.

Fireblast

You may sacrifice two Mountains rather than pay this spell's mana cost.
Fireblast deals 4 damage to any target.

Teferi's Time Twist

Exile target permanent you control. Return that card to the battlefield under its owner's control at the beginning of the next end step. If it enters as a creature, it enters with an additional +1/+1 counter on it.