Mountain

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 Matron

When Goblin Matron enters, you may search your library for a Goblin card, reveal that card, put it into your hand, then shuffle.

Goblin Grenade

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

Goblin Cohort

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

Fireblast

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

Mogg War Marshal

Echo {1}{R} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When Mogg War Marshal enters or dies, create a 1/1 red Goblin creature token.

Goblin Sledder

Sacrifice a Goblin: Target creature gets +1/+1 until end of turn.

Foundry Street Denizen

Whenever another red creature you control enters, 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, if it was kicked, creatures you control get +1/+0 and gain haste until end of turn.

Lightning Bolt

Lightning Bolt deals 3 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.