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.

Reverberate

Copy target instant or sorcery spell. You may choose new targets for the copy.

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.)

Forgotten Cave

Forgotten Cave enters tapped.
{T}: Add {R}.
Cycling {R} ({R}, Discard this card: Draw a card.)

Red Dragon

Flying
Fire Breath — When Red Dragon enters, it deals 4 damage to each opponent.

Chandra, Dressed to Kill

+1: Add {R}. Chandra, Dressed to Kill deals 1 damage to up to one target player or planeswalker.
+1: Exile the top card of your library. If it's red, you may cast it this turn.
−7: Exile the top five cards of your library. You may cast red spells from among them this turn. You get an emblem with "Whenever you cast a red spell, this emblem deals X damage to any target, where X is the amount of mana spent to cast that spell."

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.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Shock

Prodigal Pyromancer

{T}: Prodigal Pyromancer deals 1 damage to any target.

Ball Lightning

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Haste (This creature can attack and {T} as soon as it comes under your control.)
At the beginning of the end step, sacrifice this creature.