What do people think of https://github.com/jellyfin/jellyfin ?
It's open and doesn't require an account like Plex.
I have jellyfin[0] installed on my home server, then use finamp[1] on my iphone to listen on the go via streaming and usually download just the playlists to the device, which eventually get rotated.
I got so fed up with Plex constantly shoving their streaming service and nagging me to log into Plex servers when I just want to stream my own files locally that I threw my hands up and installed Jellyfin[0]. It's severely lacking in the same polish and functionality as Plex, but I'm pleased that I can run Jellyfin without ads or having to create a non-local account.
I am just gonna live this here
Also jellyfin, and I guess Emby which it was forked from
Jellyfin is modern and written in C#, but not sure if it follows any best practices. https://github.com/jellyfin/jellyfin
If you want completely FOSS setup, check out Jellyfin [0], it keeps steadily improving.
And forked as https://github.com/jellyfin/jellyfin
You may want to follow the development of Jellyfin (https://github.com/jellyfin/jellyfin), which is a fork of the Emby Media Server when it became proprietary.
Disclaimer: I'm not affiliated with Jellyfin's team, I just contributed one patch to the codebase.