Goblin Lookout

{T}, Sacrifice a Goblin: Goblin creatures get +2/+0 until end of turn.

Mountain

Goblin Warrens

{2}{R}, Sacrifice two Goblins: Create three 1/1 red Goblin creature tokens.

Goblin War Strike

Goblin War Strike deals damage to target player or planeswalker equal to the number of Goblins you control.

Goblin Offensive

Skirk Prospector

Dragon Fodder

Create two 1/1 red Goblin creature tokens.

Accelerate

Target creature gains haste until end of turn.
Draw a card.

Firefright Mage

{1}{R}, {T}, Discard a card: Target creature can't be blocked this turn except by artifact creatures and/or red creatures.

Krenko, Mob Boss

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

Goblin King

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

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Brightstone Ritual

Add {R} for each Goblin on the battlefield.

Mogg Infestation

Destroy all creatures target player controls. For each creature that died this way, that player creates two 1/1 red Goblin creature tokens.

Siege-Gang Commander

When Siege-Gang Commander enters, create three 1/1 red Goblin creature tokens.
{1}{R}, Sacrifice a Goblin: Siege-Gang Commander deals 2 damage to any target.