Raging Goblin

Haste (This creature can attack and {T} as soon as it comes under your control.)

Goblin Wardriver

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

Ferocity of the Wilds

Attacking non-Human creatures you control get +1/+0 and have trample.

Mountain

Krenko, Tin Street Kingpin

Whenever Krenko, Tin Street Kingpin attacks, put a +1/+1 counter on it, then create a number of 1/1 red Goblin creature tokens equal to Krenko's power.

Shock

Reckless One

Haste
Reckless One's power and toughness are each equal to the number of Goblins on the battlefield.

Goblin Ringleader

Haste (This creature can attack and {T} as soon as it comes under your control.)
When Goblin Ringleader enters, reveal the top four cards of your library. Put all Goblin cards revealed this way into your hand and the rest on the bottom of your library in any order.

Coordinated Assault

Up to two target creatures each get +1/+0 and gain first strike until end of turn. (They deal combat damage before creatures without first strike.)

Goblin Matron

When Goblin Matron enters, you may search your library for a Goblin card, reveal that card, put it into your hand, then shuffle.

Rummaging Goblin

Snow-Covered Mountain

Redcap Raiders

Whenever Redcap Raiders attacks, you may tap an untapped non-Human creature you control. If you do, Redcap Raiders gets +1/+1 and gains trample until end of turn.

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.

Cleaver Riot

Creatures you control gain double strike until end of turn. (They deal both first-strike and regular combat damage.)

Goblin War Drums

Creatures you control have menace. (They can't be blocked except by two or more creatures.)

Dogpile

Dogpile deals damage to any target equal to the number of attacking creatures you control.

Goblin War Strike

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

Legion Loyalist

Haste
Battalion — Whenever Legion Loyalist and at least two other creatures attack, creatures you control gain first strike and trample until end of turn and can't be blocked by creature tokens this turn.

Krenko, Mob Boss

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