[yorwba]

My guess is that if you have a place to illegally sell research chemicals online, that place could also be used to facilitate sex trafficking and will be used that way. So without explicitly targeting drug markets, FOSTA can still indirectly affect them as black markets in general.

[LaikaF]

Not generally an overlap there. As far as I'm aware there's no real one stop shop. Darknet markets have never had escort services to my knowledge.