Fireball

This spell costs {1} more to cast for each target beyond the first.
Fireball deals X damage divided evenly, rounded down, among any number of targets.

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.

Goblin Arsonist

When Goblin Arsonist dies, you may have it deal 1 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.

Mountain

Spitting Earth

Spitting Earth deals damage to target creature equal to the number of Mountains you control.

Goblin King

Other Goblins get +1/+1 and have mountainwalk.

Lava Spike

Lava Spike deals 3 damage to target player or planeswalker.

Ball Lightning

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Haste (This creature can attack and {T} as soon as it comes under your control.)
At the beginning of the end step, sacrifice this creature.

Goblin Balloon Brigade

{R}: Goblin Balloon Brigade gains flying until end of turn.

Raging Goblin

Haste (This creature can attack and {T} as soon as it comes under your control.)

Goblin Guide

Haste
Whenever Goblin Guide attacks, defending player reveals the top card of their library. If it's a land card, that player puts it into their hand.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Shock

Krenko, Mob Boss

{T}: Create X 1/1 red Goblin creature tokens, where X is the number of Goblins you control.