The plex native mobile app is pretty awful for music streaming, however "PlexAmp" available on Android and iOS is absolutely fantastic, barring a couple of minor points.
1) Requires PlexPass (iirc), 2) Makes you pick a library rather than searching/playing from all. Switching libraries is extremely quick and simple though.
Here are mine:
- Nextcloud - files, calendar, todo, contacts syncing
- Tiny Tiny RSS - RSS reader
- Wallabag - read it later, also a database of interesting things I've read so I can recall later
- Photoprism - photo organizing/tagging
- CheckMK - monitoring
- The Lounge - IRC client that connects to my ZNC bouncer
- Plex - media streaming
- Airsonic - music streaming (since Plex sucks at that)
- Gitea - git repos/issues
- Code-Server - VSC instance hosted in the browser