Sulfur Falls

Sulfur Falls enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Negate

Steam Vents

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

This spell can't be countered.
Fry deals 5 damage to target creature or planeswalker that's white or blue.

Mountain

Saheeli, Sublime Artificer

Whenever you cast a noncreature spell, create a 1/1 colorless Servo artifact creature token.
−2: Target artifact you control becomes a copy of another target artifact or creature you control until end of turn, except it's an artifact in addition to its other types.

Tale's End

Counter target activated ability, triggered ability, or legendary spell.

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Sinister Sabotage

Counter target spell.
Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

God-Eternal Kefnet

Flying
You may reveal the first card you draw each turn as you draw it. Whenever you reveal an instant or sorcery card this way, copy that card and you may cast the copy. That copy costs {2} less to cast.
When God-Eternal Kefnet dies or is put into exile from the battlefield, you may put it into its owner's library third from the top.

Crackling Drake

Flying
Crackling Drake's power is equal to the total number of instant and sorcery cards you own in exile and in your graveyard.
When Crackling Drake enters, draw a card.

Lava Coil

Lava Coil deals 4 damage to target creature. If that creature would die this turn, exile it instead.

Murmuring Mystic

Whenever you cast an instant or sorcery spell, create a 1/1 blue Bird Illusion creature token with flying.

Winged Words

This spell costs {1} less to cast if you control a creature with flying.
Draw two cards.

Essence Capture

Counter target creature spell. Put a +1/+1 counter on up to one target creature you control.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Explosion

Explosion deals X damage to any target. Target player draws X cards.

Expansion

Copy target instant or sorcery spell with mana value 4 or less. You may choose new targets for the copy.

Expansion // Explosion

Spell Pierce

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

Shock

Island

Flame Sweep

Flame Sweep deals 2 damage to each creature except for creatures you control with flying.