Lightning Strike

Lightning Strike deals 3 damage to any target.

Elvish Spirit Guide

Exile Elvish Spirit Guide from your hand: Add {G}.

Chain Lightning

Chain Lightning deals 3 damage to any target. Then that player or that permanent's controller may pay {R}{R}. If the player does, they may copy this spell and may choose a new target for that copy.

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.

Flame Rift

Flame Rift deals 4 damage to each player.

Fireblast

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

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Burning-Tree Emissary

When Burning-Tree Emissary enters the battlefield, add {R}{G}.

Simian Spirit Guide

Exile Simian Spirit Guide from your hand: Add {R}.

Channel

Until end of turn, any time you could activate a mana ability, you may pay 1 life. If you do, add {C}.

Searing Spear

Searing Spear deals 3 damage to any target.

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.)

Mountain

Orcish Lumberjack

{T}, Sacrifice a Forest: Add three mana in any combination of {R} and/or {G}.

Fireball

This spell costs {1} more to cast for each target beyond the first.
Fireball deals X damage divided evenly, rounded down, among any number of targets.