Plex is currently hosting movies, series, music, audiobooks, and podcasts. However, I'm working on moving the the audiobooks and podcasts over to Audio Bookshelf.
If there is a Movie or Series you want on plex that isn't currently available you can request it through Overseer. Keep in mind that this interface is new and has bugs. If it won't let you request something because it is "already on the server" and it's not actually there text me and I'll try to find it for you. If you try tro request something but it already shows as requested then someone else has already requested it and you don't need to request it again.
I have yet to find a clean way to request new books/podcasts; Until I do please continue adding those request to the Google Keep list.
The free user is all you need. You do NOT need a "Plex Pass" or "Remote Watch Pass" the server has a plex pass linked to it, so you don't need to purchase one to have access to premium features.