Goblin King

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

Goblin Piledriver

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

Goblin Lackey

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

Muxus, Goblin Grandee

When Muxus, Goblin Grandee enters the battlefield, reveal the top six cards of your library. Put all Goblin creature cards with mana value 5 or less from among them onto the battlefield and the rest on the bottom of your library in a random order.
Whenever Muxus attacks, it gets +1/+1 until end of turn for each other Goblin you control.

Goblin Recruiter

When Goblin Recruiter enters the battlefield, search your library for any number of Goblin cards, reveal them, then shuffle and put those cards on top in any order.

Goblin Chainwhirler

First strike
When Goblin Chainwhirler enters the battlefield, it deals 1 damage to each opponent and each creature and planeswalker they control.

Goblin Matron

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

Goblin Ringleader

Haste (This creature can attack and {T} as soon as it comes under your control.)
When Goblin Ringleader enters the battlefield, 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.

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 Goblin Rabblemaster attacks, it gets +1/+0 until end of turn for each other attacking Goblin.

Krenko, Mob Boss

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

Goblin Trashmaster

Other Goblins you control get +1/+1.
Sacrifice a Goblin: Destroy target artifact.

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.