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.

Mountain

Brightstone Ritual

Add {R} for each Goblin on the battlefield.

Goblin King

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

Goblin Lackey

Whenever Goblin Lackey deals damage to a player, you may put a Goblin permanent card from your hand onto the battlefield.

Skirk Prospector

Goblin Caves

Enchant land
As long as enchanted land is a basic Mountain, Goblin creatures get +0/+2.

Akki Rockspeaker

Intimidator Initiate

Whenever a player casts a red spell, you may pay {1}. If you do, target creature can't block this turn.

Goblin Roughrider

Quest for the Goblin Lord

Whenever a Goblin you control enters, you may put a quest counter on Quest for the Goblin Lord.
As long as Quest for the Goblin Lord has five or more quest counters on it, creatures you control get +2/+0.

Goblin Shortcutter

When Goblin Shortcutter enters, target creature can't block this turn.

Krenko, Mob Boss

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

Goblin Lookout

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

Bloodmark Mentor

Red creatures you control have first strike.

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.

Goblin Arsonist

When Goblin Arsonist dies, you may have it deal 1 damage to any target.

Kiki-Jiki, Mirror Breaker

Haste
{T}: Create a token that's a copy of target nonlegendary creature you control, except it has haste. Sacrifice it at the beginning of the next end step.

Goblin Sledder

Sacrifice a Goblin: Target creature gets +1/+1 until end of turn.

Goblin Wardriver

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)

Voracious Dragon

Flying
Devour 1 (As this enters, you may sacrifice any number of creatures. This creature enters with that many +1/+1 counters on it.)
When Voracious Dragon enters, it deals damage to any target equal to twice the number of Goblins it devoured.

Goblin Warchief

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

Barrage of Expendables

{R}, Sacrifice a creature: Barrage of Expendables deals 1 damage to any target.

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.

Horde of Boggarts

Menace (This creature can't be blocked except by two or more creatures.)
Horde of Boggarts's power and toughness are each equal to the number of red permanents you control.