Fireblast

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

Goblin Grenade

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

Sparksmith

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

Mudbrawler Cohort

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

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.)

Goblin Cohort

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

Mountain

Foundry Street Denizen

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

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Mogg Conscripts

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

Burning-Tree Emissary

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

Goblin Bushwhacker

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