Don't Have

Goblin Tinkerer

{R}, {T}: Destroy target artifact. That artifact deals damage equal to its mana value to Goblin Tinkerer.

Goblin Warchief

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

Getting

Goblin Lackey

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

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.

Barbarian Ring

{T}: Add {R}. Barbarian Ring deals 1 damage to you.
Threshold — {R}, {T}, Sacrifice Barbarian Ring: It deals 2 damage to any target. Activate only if seven or more cards are in your graveyard.

Have

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Mogg Fanatic

Sacrifice Mogg Fanatic: It deals 1 damage to any target.

Skirk Prospector

Goblin Pyromancer

When Goblin Pyromancer enters, Goblin creatures get +3/+0 until end of turn.
At the beginning of the end step, destroy all Goblins.

Goblin Sharpshooter

Goblin Sharpshooter doesn't untap during your untap step.
Whenever a creature dies, untap Goblin Sharpshooter.
{T}: Goblin Sharpshooter deals 1 damage to any target.

Clickslither

Haste
Sacrifice a Goblin: Clickslither gets +2/+2 and gains trample until end of turn.

Goblin King

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

Mountain

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 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.

Gempalm Incinerator

Cycling {1}{R} ({1}{R}, Discard this card: Draw a card.)
When you cycle Gempalm Incinerator, you may have it deal X damage to target creature, where X is the number of Goblins on the battlefield.

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.