Kiln Fiend

Whenever you cast an instant or sorcery spell, Kiln Fiend gets +3/+0 until end of turn.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Forgotten Cave

Forgotten Cave enters tapped.
{T}: Add {R}.
Cycling {R} ({R}, Discard this card: Draw a card.)

Rift Bolt

Rift Bolt deals 3 damage to any target.
Suspend 1—{R} (Rather than cast this card from your hand, you may pay {R} and exile it with a time counter on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Curse of the Pierced Heart

Enchant player
At the beginning of enchanted player's upkeep, Curse of the Pierced Heart deals 1 damage to that player or a planeswalker that player controls.

Epiphany Storm

Enchant creature
Enchanted creature has "{R}, {T}, Discard a card: Draw a card."

Wild Guess

As an additional cost to cast this spell, discard a card.
Draw two cards.

Dangerous Wager

Strangle

Strangle deals 3 damage to target creature or planeswalker.

Disintegrate

Disintegrate deals X damage to any target. If it's a creature, it can't be regenerated this turn, and if it would die this turn, exile it instead.

Skewer the Critics

Spectacle {R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Skewer the Critics deals 3 damage to any target.

Spire Barrage

Spire Barrage deals damage to any target equal to the number of Mountains you control.

Thermo-Alchemist

Defender
{T}: Thermo-Alchemist deals 1 damage to each opponent.
Whenever you cast an instant or sorcery spell, untap Thermo-Alchemist.

Voldaren Epicure

When Voldaren Epicure enters, it deals 1 damage to each opponent. Create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")

Searing Blaze

Searing Blaze deals 1 damage to target player or planeswalker and 1 damage to target creature that player or that planeswalker's controller controls.
Landfall — If you had a land enter the battlefield under your control this turn, Searing Blaze deals 3 damage to that player or planeswalker and 3 damage to that creature instead.