I don't know what the Goblin theme will be, but I am imagining boisterous, bumbling goblins, like the ones in Warcraft. Anyways, here's my idea: "Strike Team Delta". Art: three goblins dressed like a ninja, a wizard, and an incredibly awesome warrior badass. They are all striking uber-cool poses, but they have crappy/silly goblin equipment.

Domain: GGX
Flux: 4
A:3
H:1
M:4
V:3
R:0

Activated ability: Place a Goblin Commando in three adjacent spaces, then Sacrifice Strike Team Delta.

Goblin Commando
Domain: G
Flux: 1
A:1
H:1
M:3
V:3
R:0