Need some ideas...

Does anyone here have any idea of what a good Goblin racial orb, would be?
Humans have the Orb of Fire, Orcs the Orb of Lightning, Undead the Orb of Corruption, and the Night Elves the Orb of Venom. But I can't really think of what a fitting Orb for Goblins would be.
Also, if you have any ideas for any other items that would fit in a Goblin market, please go ahead and share them.

Orb of Mischief / Iron / Steel / Earth / Thievery

Dono.

I meant more in terms of effects.

Quick Idea: Bonus damage vs structures

Orb of Pyromaniacs, has an explosion effect like mines

goblins are chaotic, unrpredictable and unreliable, and in warcraft kind of cartoonish. Id go with orb of boom-boom or krash-bang or something like that with a decent ability that has a terrible drawback. Like +30 damage but
-25% attack speed or something

Context? I'll assume you mean strictly Warcraft 3 Goblins.
In that case, there's 3 spheres you could follow:

Invention. Spawn some kind of gizmo?
Money. Perhaps extra money per kill or over time. How to truly 'pawn' your enemy.
Destruction. Extra structure damage, random effects.

Yeah, Warcraft Goblins only. So far I really like the money and the building damage orbs.

You could twist destruction to malfunction. Random silence/slow/freeze effects?
Jinx.

Orb of Greed. Every attack, there is a chance to lose/gain gold/resource.