Lightning Axe

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

Devour in Flames

As an additional cost to cast this spell, return a land you control to its owner's hand.
Devour in Flames deals 5 damage to target creature or planeswalker.

Scorching Shot

Scorching Shot deals 5 damage to target creature.

Roast

Roast deals 5 damage to target creature without flying.

Betrayer's Bargain

As an additional cost to cast this spell, sacrifice a creature or enchantment or pay {2}.
Betrayer's Bargain deals 5 damage to target creature. If that creature would die this turn, exile it instead.

Imodane, the Pyrohammer

Whenever an instant or sorcery spell you control that targets only a single creature deals damage to that creature, Imodane deals that much damage to each opponent.

Tears of Valakut

This spell can't be countered.
Tears of Valakut deals 5 damage to target creature with flying.

Flame Slash

Flame Slash deals 4 damage to target creature.

Lava Coil

Lava Coil deals 4 damage to target creature. If that creature would die this turn, exile it instead.