Ruby Medallion

Red spells you cast cost {1} less to cast.

Jaya's Immolating Inferno

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Jaya's Immolating Inferno deals X damage to each of up to three targets.

Screaming Nemesis

Haste
Whenever this creature is dealt damage, it deals that much damage to any other target. If a player is dealt damage this way, they can't gain life for the rest of the game.

Razorkin Needlehead

This creature has first strike during your turn.
Whenever an opponent draws a card, this creature deals 1 damage to them.

Banefire

Banefire deals X damage to any target.
If X is 5 or more, this spell can't be countered and the damage can't be prevented.

Solphim, Mayhem Dominus

If a source you control would deal noncombat damage to an opponent or a permanent an opponent controls, it deals double that damage to that player or permanent instead.
{1}{R/P}{R/P}, Discard two cards: Put an indestructible counter on Solphim. ({R/P} can be paid with either {R} or 2 life.)

Searing Spear

Searing Spear deals 3 damage to any target.

Mountain

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Incinerate

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

Thermo-Alchemist

Defender
{T}: This creature deals 1 damage to each opponent.
Whenever you cast an instant or sorcery spell, untap this creature.

Looming Spires

This land enters tapped.
When this land enters, target creature gets +1/+1 and gains first strike until end of turn.
{T}: Add {R}.

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.

Play with Fire

Play with Fire deals 2 damage to any target. If a player is dealt damage this way, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

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.

Chandra, Flame's Fury

+1: Chandra deals 2 damage to any target.
−2: Chandra deals 4 damage to target creature and 2 damage to that creature's controller.
−8: Chandra deals 10 damage to target player and each creature that player controls.

Hungry Flames

Hungry Flames deals 3 damage to target creature and 2 damage to target player or planeswalker.