Shock

Firebrand Archer

Whenever you cast a noncreature spell, this creature deals 1 damage to each opponent.

Kessig Flamebreather

Whenever you cast a noncreature spell, Kessig Flamebreather deals 1 damage to each opponent.

Guttersnipe

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

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.

End the Festivities

End the Festivities deals 1 damage to each opponent and each creature and planeswalker they control.

Young Pyromancer

Whenever you cast an instant or sorcery spell, create a 1/1 red Elemental creature token.

Mechanized Warfare

If a red or artifact source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus 1 instead.

Thermo-Alchemist

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

Viashino Pyromancer

When this creature enters, it deals 2 damage to target player or planeswalker.

Hidetsugu's Second Rite

If target player has exactly 10 life, Hidetsugu's Second Rite deals 10 damage to that player.

Mountain

Efreet Flamepainter

Double strike
Whenever Efreet Flamepainter deals combat damage to a player, you may cast target instant or sorcery card from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Fanatical Firebrand

Haste (This creature can attack and {T} as soon as it comes under your control.)
{T}, Sacrifice this creature: It deals 1 damage to any target.