Why wouldn’t just about anything be ok? Using real character of someone on ship would be some sort of violation, but after that, even knowing someone’s holodeck preferences could easily be a breach of privacy
Hate to go there but I can't think of other examples. Cartoon sexual images of children are illegal in many countries. So you can imagine there might be limits despite it not being real.
Privacy doesn't excist on a starfleet ship. They'll search your private log and the doc will tell them anything about your medical history if your 5 minutes late to the pickup after the latest mission