Goblin King

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

Goblin Assault

At the beginning of your upkeep, create a 1/1 red Goblin creature token with haste.
Goblin creatures attack each combat if able.

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

Haste (This creature can attack and {T} as soon as it comes under your control.)
Other Goblin creatures you control get +1/+1 and have haste.

This spell can't be countered.
Volcanic Fallout deals 2 damage to each creature and each player.

Whenever Mogg Maniac is dealt damage, it deals that much damage to target opponent or planeswalker.

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

Lightning Bolt deals 3 damage to any target.

Goblin spells you cast cost {1} less to cast.
Goblins you control have haste.