Goblin Fire Fiend

Haste
Goblin Fire Fiend must be blocked if able.
{R}: Goblin Fire Fiend gets +1/+0 until end of turn.

Ib Halfheart, Goblin Tactician

Whenever another Goblin you control becomes blocked, sacrifice it. If you do, it deals 4 damage to each creature blocking it.
Sacrifice two Mountains: Create two 1/1 red Goblin creature tokens.

Akki Raider

Whenever a land is put into a graveyard from the battlefield, Akki Raider gets +1/+0 until end of turn.

Ore-Scale Guardian

This spell costs {1} less to cast for each land card in your graveyard.
Flying, haste

Petravark

When Petravark enters, exile target land.
When Petravark leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Krenko, Mob Boss

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

Cavalier of Flame

{1}{R}: Creatures you control get +1/+0 and gain haste until end of turn.
When Cavalier of Flame enters, discard any number of cards, then draw that many cards.
When Cavalier of Flame dies, it deals X damage to each opponent and each planeswalker they control, where X is the number of land cards in your graveyard.