Hi! We don't have any pre-existing rules about what types of PBs can be used. We would only ask that, for live action PBs in particular, the person being used is 18+ and that they are a public figure, such as an actor/model/singer. If they have publicly stated that they don't want their image used in such a way, we ask that players respect that as well. If the PB you would like to use fits those criteria, they're fine!