Goblin King

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

Krenko's Command

Create two 1/1 red Goblin creature tokens.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Mountain

Goblin Chieftain

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.

Dragon Fodder

Krenko, Mob Boss

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

Hordeling Outburst

Create three 1/1 red Goblin creature tokens.

Goblin Grenade

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

Goblin Instigator

When Goblin Instigator enters, create a 1/1 red Goblin creature token.

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.

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.