Lightning Strike

Lightning Strike deals 3 damage to any target.

Shock

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}.

Skewer the Critics

Spectacle {R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Skewer the Critics deals 3 damage to any target.

Fanatical Firebrand

Haste (This creature can attack and {T} as soon as it comes under your control.)
{T}, Sacrifice this creature: It deals 1 damage to any target.

The Flame of Keld

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Discard your hand.
II — Draw two cards.
III — If a red source you control would deal damage to a permanent or player this turn, it deals that much damage plus 2 to that permanent or player instead.

Spear Spewer

Defender
{T}: Spear Spewer deals 1 damage to each player.

Goblin Chainwhirler

First strike
When Goblin Chainwhirler enters, it deals 1 damage to each opponent and each creature and planeswalker they control.

Light Up the Stage

Spectacle {R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Mountain

Ember Hauler

{1}, Sacrifice Ember Hauler: It deals 2 damage to any target.

Goblin Ringleader

Haste (This creature can attack and {T} as soon as it comes under your control.)
When Goblin Ringleader enters, reveal the top four cards of your library. Put all Goblin cards revealed this way into your hand and the rest on the bottom of your library in any order.