Steam Vents

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

Bedlam Reveler

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
Prowess
When Bedlam Reveler enters, discard your hand, then draw three cards.

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Stormwing Entity

This spell costs {2}{U} less to cast if you've cast an instant or sorcery spell this turn.
Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Stormwing Entity enters, scry 2.

Gut Shot

({R/P} can be paid with either {R} or 2 life.)
Gut Shot deals 1 damage to any target.

Assault Strobe

Target creature gains double strike until end of turn. (It deals both first-strike and regular combat damage.)

Dragon's Claw

Whenever a player casts a red spell, you may gain 1 life.

Manamorphose

Add two mana in any combination of colors.
Draw a card.

Burst Lightning

Kicker {4} (You may pay an additional {4} as you cast this spell.)
Burst Lightning deals 2 damage to any target. If this spell was kicked, it deals 4 damage instead.

Monastery Swiftspear

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

Wooded Foothills

{T}, Pay 1 life, Sacrifice Wooded Foothills: Search your library for a Mountain or Forest card, put it onto the battlefield, then shuffle.

Crash Through

Creatures you control gain trample until end of turn. (A creature with trample can deal excess combat damage to the player or planeswalker it's attacking.)
Draw a card.

Soul-Guide Lantern

When Soul-Guide Lantern enters, exile target card from a graveyard.
{T}, Sacrifice Soul-Guide Lantern: Exile each opponent's graveyard.
{1}, {T}, Sacrifice Soul-Guide Lantern: Draw a card.

Sprite Dragon

Flying, haste
Whenever you cast a noncreature spell, put a +1/+1 counter on Sprite Dragon.

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.)

Flame Slash

Flame Slash deals 4 damage to target creature.

Fiery Islet

{T}, Pay 1 life: Add {U} or {R}.
{1}, {T}, Sacrifice Fiery Islet: Draw a card.

Aether Gust

Choose target spell or permanent that's red or green. Its owner puts it on the top or bottom of their library.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Light Up the Stage

Spectacle {R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Mutagenic Growth

({G/P} can be paid with either {G} or 2 life.)
Target creature gets +2/+2 until end of turn.

Spirebluff Canal

Spirebluff Canal enters tapped unless you control two or fewer other lands.
{T}: Add {U} or {R}.

Soul-Scar Mage

Prowess
If a source you control would deal noncombat damage to a creature an opponent controls, put that many -1/-1 counters on that creature instead.

Mountain

Arid Mesa

{T}, Pay 1 life, Sacrifice Arid Mesa: Search your library for a Mountain or Plains card, put it onto the battlefield, then shuffle.