Rundvelt Hordemaster

Other Goblins you control get +1/+1.
Whenever Rundvelt Hordemaster or another Goblin you control dies, exile the top card of your library. If it's a Goblin creature card, you may cast that card until the end of your next turn.

Frenzied Goblin

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

Brightstone Ritual

Add {R} for each Goblin on the battlefield.

Mountain

Hobgoblin Bandit Lord

Other Goblins you control get +1/+1.
{R}, {T}: Hobgoblin Bandit Lord deals damage equal to the number of Goblins that entered the battlefield under your control this turn to any target.

Skirk Prospector

Goblin War Strike

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

Conspicuous Snoop

Play with the top card of your library revealed.
You may cast Goblin spells from the top of your library.
As long as the top card of your library is a Goblin card, Conspicuous Snoop has all activated abilities of that card.

Goblin Lackey

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

Goblin Instigator

When Goblin Instigator enters, create a 1/1 red Goblin creature token.

Krenko, Mob Boss

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

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.

Muxus, Goblin Grandee

When Muxus, Goblin Grandee enters, 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 Warchief

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

Lightning Bolt

Lightning Bolt deals 3 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.

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.

Warren Instigator

Double strike
Whenever Warren Instigator deals damage to an opponent, you may put a Goblin creature card from your hand onto the battlefield.