Lava Spike

Lava Spike deals 3 damage to target player or planeswalker.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Mountain

Lightning Strike

Lightning Strike deals 3 damage to any target.

Conjurer's Bauble

{T}, Sacrifice Conjurer's Bauble: Put up to one target card from your graveyard on the bottom of your library. Draw a card.

Play with Fire

Play with Fire deals 2 damage to any target. If a player is dealt damage this way, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Desperate Ritual

Add {R}{R}{R}.
Splice onto Arcane {1}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Mishra's Bauble

{T}, Sacrifice Mishra's Bauble: Look at the top card of target player's library. Draw a card at the beginning of the next turn's upkeep.

Chromatic Sphere

{1}, {T}, Sacrifice Chromatic Sphere: Add one mana of any color. Draw a card.

Incinerate

Incinerate deals 3 damage to any target. A creature dealt damage this way can't be regenerated this turn.

Skullcrack

Players can't gain life this turn. Damage can't be prevented this turn. Skullcrack deals 3 damage to target player or planeswalker.

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.