Red creatures with green support.

1 drop (8)

Foundry Street Denizen - Goblin grower

Frenzied Goblin - Goblin with occasionally useful ability.

2 drop (8)

Dragon Fodder - Goblins

Mardu Scout - Goblin

3 drop (12)

Goblin Rabblemaster - Goblins

Hordeling Outburst - Goblins

Kolaghan Forerunners - Might swap this out for Jeering Instigator since it's not a goblin. My idea was that it'd be a good target for Collected Company because hopefully by turn 4 it would be 5+ power.

4 drop (6)

Collected Company - I would say 4 is too many at this cmc but at instant speed, I don't know.

Fated Conflagration - Flexible on this one. Maybe Purphoros, God of the Forge would be better.

Xenagos, the Reveler - More mana or tokens. Probably won't make it to his ultimate, but it'd be interesting if I did.

5 drop (4)

Shamanic Revelation - Restock your hand. Maybe a little lifegain.

Whisperwood Elemental - Good insurance since everyone will be trying to wipe your goblins. I might move this to the sideboard though since that might be more likely on G2.