The Horde Guild Directory is always a great place to start!
I’d also like to direct your attention to some other guilds whose members I see around a lot! Keep in mind, what follows is not a comprehensive list and others should feel free to elaborate/add to it.
The Oyster Business: Mostly goblin RP crime guild. Honestly, I think this might be the closest to what you might be looking for, hence me putting it at the top of the list.
Frostbite Contingent: Partially Goblin owned mercenary company. Not sure how criminal they are, but they are mercenaries. That requires a certain kind of pragmatism.
Gearpunk Dynamics: Mostly goblin business, not criminal as far as I know. They don’t sell weapons at the very least.
And of course, the wonderful and super amazing…
Firebrand Enterprises : Goblin owned mercantile guild. Less criminal and more comically amoral in pursuit of profit.