Rorix Bladewing

Goblin Warchief

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

Ring of Valkas

Equipped creature has haste. (It can attack and {T} no matter when it came under your control.)
At the beginning of your upkeep, put a +1/+1 counter on equipped creature if it's red.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Tuktuk the Explorer

Haste
When Tuktuk the Explorer dies, create Tuktuk the Returned, a legendary 5/5 colorless Goblin Golem artifact creature token.

Goblin King

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

Mountain

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Maraxus of Keld

Maraxus of Keld's power and toughness are each equal to the number of untapped artifacts, creatures, and lands you control.

Krenko, Mob Boss

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

Frenzied Goblin

Whenever this creature attacks, you may pay {R}. If you do, target creature can't block this turn.

Akki Underminer

Whenever Akki Underminer deals combat damage to a player, that player sacrifices a permanent of their choice.

Goblin Fireslinger

{T}: Goblin Fireslinger deals 1 damage to target player or planeswalker.

Shock

Ben-Ben, Akki Hermit

{T}: Ben-Ben, Akki Hermit deals damage to target attacking creature equal to the number of untapped Mountains you control.

Goblin Balloon Brigade

{R}: Goblin Balloon Brigade gains flying until end of turn.

Goblin Roughrider

Tenza, Godo's Maul

Equipped creature gets +1/+1. As long as it's legendary, it gets an additional +2/+2. As long as it's red, it has trample.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Goblin Piker

Raging Goblin

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

Goblin Arsonist

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

Goblin Tunneler

{T}: Target creature with power 2 or less can't be blocked this 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.

Akki Coalflinger

First strike
{R}, {T}: Attacking creatures gain first strike until end of turn.

Preyseizer Dragon

Flying
Devour 2 (As this enters, you may sacrifice any number of creatures. This creature enters with twice that many +1/+1 counters on it.)
Whenever Preyseizer Dragon attacks, it deals damage to any target equal to the number of +1/+1 counters on Preyseizer Dragon.