The classic three of organised crime are: Dice, Booze and Women.
Drugs came much later.
They could offer gambling to those how have been kicke out of the regular establishments.
They can sell booze to the Sinless, and other things, because remember, the Sinless are not part of the system theycannot alk into a store !!
( Work in our sweatshop and we will give you...food)
Running a Stripclub /Prostitution depends on your player group.....
However I like the Idea of starting a place that entertains Orcs and Trolls By having Orc and Troll women dance !!) and sell Hurlg at the bar, because the rassist clubs refuse service

... Now that I think about it I need to set up a place for my next Johnson meetup...