Flameblast Dragon

Flying
Whenever Flameblast Dragon attacks, you may pay {X}{R}. If you do, Flameblast Dragon deals X damage to any target.

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.)

Rolling Thunder

Rolling Thunder deals X damage divided as you choose among any number of targets.

Galvanic Blast

Galvanic Blast deals 2 damage to any target.
Metalcraft — Galvanic Blast deals 4 damage instead if you control three or more artifacts.

Chandra Ablaze

+1: Discard a card. If a red card is discarded this way, Chandra Ablaze deals 4 damage to any target.
−2: Each player discards their hand, then draws three cards.
−7: Cast any number of red instant and/or sorcery cards from your graveyard without paying their mana costs.

Kindle

Kindle deals X damage to any target, where X is 2 plus the number of cards named Kindle in all graveyards.

Firebolt

Firebolt deals 2 damage to any target.
Flashback {4}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Shock

Gathan Raiders

Hellbent — Gathan Raiders gets +2/+2 as long as you have no cards in hand.
Morph—Discard a card. (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Dragon Whelp

Flying
{R}: Dragon Whelp gets +1/+0 until end of turn. If this ability has been activated four or more times this turn, sacrifice Dragon Whelp at the beginning of the next end step.

Mountain

Lava Spike

Lava Spike deals 3 damage to target player or planeswalker.

Cone of Flame

Cone of Flame deals 1 damage to any target, 2 damage to another target, and 3 damage to a third target.

Jiwari, the Earth Aflame

{X}{R}, {T}: Jiwari, the Earth Aflame deals X damage to target creature without flying.
Channel — {X}{R}{R}{R}, Discard Jiwari: Jiwari deals X damage to each creature without flying.

Galvanoth

At the beginning of your upkeep, you may look at the top card of your library. You may cast it without paying its mana cost if it's an instant or sorcery spell.

Pyroclasm

Pyroclasm deals 2 damage to each creature.

Volcanic Hammer

Volcanic Hammer deals 3 damage to any target.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Pyromancer's Gauntlet

If a red instant or sorcery spell you control or a red planeswalker you control would deal damage to a permanent or player, it deals that much damage plus 2 to that permanent or player instead.

Slith Firewalker

Haste
Whenever Slith Firewalker deals combat damage to a player, put a +1/+1 counter on it.

Flametongue Kavu

When Flametongue Kavu enters, it deals 4 damage to target creature.

Incinerate

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

Jaya Ballard, Task Mage

{R}, {T}, Discard a card: Destroy target blue permanent.
{1}{R}, {T}, Discard a card: Jaya Ballard, Task Mage deals 3 damage to any target. A creature dealt damage this way can't be regenerated this turn.
{5}{R}{R}, {T}, Discard a card: Jaya Ballard deals 6 damage to each creature and each player.

Landslide

Sacrifice any number of Mountains. Landslide deals that much damage to target player or planeswalker.