Guttersnipe

Whenever you cast an instant or sorcery spell, Guttersnipe deals 2 damage to each opponent.

Searing Spear

Searing Spear deals 3 damage to any target.

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.

Pyre Hound

Trample
Whenever you cast an instant or sorcery spell, put a +1/+1 counter on Pyre Hound.

Monastery Swiftspear

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

Lava Spike

Lava Spike deals 3 damage to target player or planeswalker.

Electrostatic Field

Defender
Whenever you cast an instant or sorcery spell, Electrostatic Field deals 1 damage to each opponent.

Bloodfeather Phoenix

Flying
Bloodfeather Phoenix can't block.
Whenever an instant or sorcery spell you control deals damage to an opponent or battle, you may pay {R}. If you do, return Bloodfeather Phoenix from your graveyard to the battlefield. It gains haste until end of turn.

Furnace of Rath

If a source would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Grapeshot

Grapeshot deals 1 damage to any target.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Roiling Vortex

At the beginning of each player's upkeep, Roiling Vortex deals 1 damage to them.
Whenever a player casts a spell, if no mana was spent to cast that spell, Roiling Vortex deals 5 damage to that player.
{R}: Your opponents can't gain life this turn.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Chandra, Torch of Defiance

+1: Exile the top card of your library. You may cast that card. If you don't, Chandra, Torch of Defiance deals 2 damage to each opponent.
+1: Add {R}{R}.
−3: Chandra, Torch of Defiance deals 4 damage to target creature.
−7: You get an emblem with "Whenever you cast a spell, this emblem deals 5 damage to any target."

Relic Robber

Haste
Whenever Relic Robber deals combat damage to a player, that player creates a 0/1 colorless Goblin Construct artifact creature token with "This creature can't block" and "At the beginning of your upkeep, this creature deals 1 damage to you."

Lightning Bolt

Lightning Bolt deals 3 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.

Chandra's Phoenix

Flying
Haste (This creature can attack and {T} as soon as it comes under your control.)
Whenever an opponent is dealt damage by a red instant or sorcery spell you control or by a red planeswalker you control, return Chandra's Phoenix from your graveyard to your hand.

Lightning Axe

As an additional cost to cast this spell, discard a card or pay {5}.
Lightning Axe deals 5 damage to target creature.

Torbran, Thane of Red Fell

If a red source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus 2 instead.

Seething Song

Fiery Confluence

Choose three. You may choose the same mode more than once.
• Fiery Confluence deals 1 damage to each creature.
• Fiery Confluence deals 2 damage to each opponent.
• Destroy target artifact.

Fiery Temper

Fiery Temper deals 3 damage to any target.
Madness {R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Shock

Runaway Steam-Kin

Whenever you cast a red spell, if Runaway Steam-Kin has fewer than three +1/+1 counters on it, put a +1/+1 counter on Runaway Steam-Kin.
Remove three +1/+1 counters from Runaway Steam-Kin: Add {R}{R}{R}.