Vexing Devil

When Vexing Devil enters the battlefield, any opponent may have it deal 4 damage to them. If a player does, sacrifice Vexing Devil.

Lava Spike

Lava Spike deals 3 damage to target player or planeswalker.

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.)

Grim Lavamancer

{R}, {T}, Exile two cards from your graveyard: Grim Lavamancer deals 2 damage to any target.

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.

Skullcrack

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

Searing Blood

Searing Blood deals 2 damage to target creature. When that creature dies this turn, Searing Blood deals 3 damage to the creature's controller.

Eidolon of the Great Revel

Whenever a player casts a spell with mana value 3 or less, Eidolon of the Great Revel deals 2 damage to that player.

Mountain

Shard Volley

As an additional cost to cast this spell, sacrifice a land.
Shard Volley deals 3 damage to any target.

Seal of Fire

Sacrifice Seal of Fire: It deals 2 damage to any target.

Dragon's Claw

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

Soul-Guide Lantern

When Soul-Guide Lantern enters the battlefield, 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.

Smash to Smithereens

Destroy target artifact. Smash to Smithereens deals 3 damage to that artifact's controller.

Chandra's Incinerator

This spell costs {X} less to cast, where X is the total amount of noncombat damage dealt to your opponents this turn.
Trample
Whenever a source you control deals noncombat damage to an opponent, Chandra's Incinerator deals that much damage to target creature or planeswalker that player controls.

Shrine of Burning Rage

At the beginning of your upkeep or whenever you cast a red spell, put a charge counter on Shrine of Burning Rage.
{3}, {T}, Sacrifice Shrine of Burning Rage: It deals damage equal to the number of charge counters on it to any target.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Monastery Swiftspear

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