Have

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.

Mountain

Seething Song

Infernal Plunge

As an additional cost to cast this spell, sacrifice a creature.
Add {R}{R}{R}.

Desperate Ritual

Add {R}{R}{R}.
Splice onto Arcane {1}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Mana Geyser

Add {R} for each tapped land your opponents control.

Storm-Kiln Artist

Storm-Kiln Artist gets +1/+0 for each artifact you control.
Magecraft — Whenever you cast or copy an instant or sorcery spell, create a Treasure token.

Pyretic Ritual

Rite of Flame

Add {R}{R}, then add {R} for each card named Rite of Flame in each graveyard.

Runaway Steam-Kin

Whenever you cast a red spell, if Runaway Steam-Kin has fewer than three +1/+1 counters on it, put a +1/+1 counter on Runaway Steam-Kin.
Remove three +1/+1 counters from Runaway Steam-Kin: Add {R}{R}{R}.

Stuffy Doll

Indestructible
As Stuffy Doll enters, choose a player.
Whenever Stuffy Doll is dealt damage, it deals that much damage to the chosen player.
{T}: Stuffy Doll deals 1 damage to itself.

Fire Diamond

Fire Diamond enters tapped.
{T}: Add {R}.

Star of Extinction

Destroy target land. Star of Extinction deals 20 damage to each creature and each planeswalker.