Mountain

Electrickery

Electrickery deals 1 damage to target creature you don't control.
Overload {1}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Mogg Conscripts

Mogg Conscripts can't attack unless you've cast a creature spell this turn.

Goblin Cohort

Goblin Cohort can't attack unless you've cast a creature spell this turn.

Burning-Tree Emissary

When Burning-Tree Emissary enters the battlefield, add {R}{G}.

Goblin Grenade

As an additional cost to cast this spell, sacrifice a Goblin.
Goblin Grenade deals 5 damage to any target.

Fireblast

You may sacrifice two Mountains rather than pay this spell's mana cost.
Fireblast deals 4 damage to any target.

Goblin Heelcutter

Whenever Goblin Heelcutter attacks, target creature can't block this turn.
Dash {2}{R} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

Gorilla Shaman

{X}{X}{1}: Destroy target noncreature artifact with mana value X.

Flame Slash

Flame Slash deals 4 damage to target creature.

Jackal Familiar

Jackal Familiar can't attack or block alone.

Red Elemental Blast

Choose one —
• Counter target blue spell.
• Destroy target blue permanent.

Mudbrawler Cohort

Haste
Mudbrawler Cohort gets +1/+1 as long as you control another red creature.

Foundry Street Denizen

Whenever another red creature enters the battlefield under your control, Foundry Street Denizen gets +1/+0 until end of turn.

Goblin Bushwhacker

Kicker {R} (You may pay an additional {R} as you cast this spell.)
When Goblin Bushwhacker enters the battlefield, if it was kicked, creatures you control get +1/+0 and gain haste until end of turn.

Valley Dasher

Haste
Valley Dasher attacks each combat if able.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Boulder Rush

Target creature gets +2/+0 until end of turn. (Then exile this card. You may cast the creature later from exile.)

Rimrock Knight

Rimrock Knight // Boulder Rush

Sparksmith

{T}: Sparksmith deals X damage to target creature and X damage to you, where X is the number of Goblins on the battlefield.

Chain Lightning

Chain Lightning deals 3 damage to any target. Then that player or that permanent's controller may pay {R}{R}. If the player does, they may copy this spell and may choose a new target for that copy.