Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Goblin King

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

Blood Moon

Mons's Goblin Raiders

Goblin Balloon Brigade

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

Mountain

Goblin Digging Team

{T}, Sacrifice Goblin Digging Team: Destroy target Wall.

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.

Goblins of the Flarg

Mountainwalk (This creature can't be blocked as long as defending player controls a Mountain.)
When you control a Dwarf, sacrifice Goblins of the Flarg.

Goblin Shrine

Enchant land
As long as enchanted land is a basic Mountain, Goblin creatures get +1/+0.
When Goblin Shrine leaves the battlefield, it deals 1 damage to each Goblin creature.

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 Grenade

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