Brightstone Ritual

Add {R} for each Goblin on the battlefield.

Krenko, Mob Boss

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

Mountain

Goblin Rabblemaster

Other Goblin creatures you control attack each combat if able.
At the beginning of combat on your turn, create a 1/1 red Goblin creature token with haste.
Whenever this creature attacks, it gets +1/+0 until end of turn for each other attacking Goblin.

Hordeling Outburst

Create three 1/1 red Goblin creature tokens.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

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.

Goblin Warchief

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

Siege-Gang Commander

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

Goblin Grenade

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

Foundry Street Denizen

Whenever another red creature you control enters, this creature gets +1/+0 until end of turn.

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.

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.