Goblin Piledriver

Protection from blue (This creature can't be blocked, targeted, dealt damage, or enchanted by anything blue.)
Whenever this creature attacks, it gets +2/+0 until end of turn for each other attacking Goblin.

Goblin Warchief

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

Krenko's Command

Create two 1/1 red Goblin creature tokens.

Guttersnipe

Whenever you cast an instant or sorcery spell, this creature deals 2 damage to each opponent.

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.

Shared Animosity

Whenever a creature you control attacks, it gets +1/+0 until end of turn for each other attacking creature that shares a creature type with it.

Goblin Matron

When this creature 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.

Dragon Fodder

Krenko, Mob Boss

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

Impact Tremors

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

Mountain

Warren Instigator

Double strike
Whenever this creature deals damage to an opponent, you may put a Goblin creature card from your hand onto the battlefield.