Free and Open Source Software

conduit is a lightweight Matrix homeserver. If you tried running synapse and found it to be an utter mess, conduit is much better!

mpd is a music server daemon with many clients. It scans your music (either stored locally or on a network) and creates a database (either stored locally or accessed from another mpd server on the network).

minidlna is a ~~DLNA~~ReadyMedia server which is a plug and play media server. Many hardware devices (e.g. AVRs) which don't support anything else do support DLNA, so you can e.g. serve music or video directly to your AVR instead of needing a set top box like an Apple TV or Roku.

If you have a problem with collecting machines like I do, set up DNS with dnsmasq. It's pretty easy to get started, all you need to do is write your /etc/hosts file (and, likely, disable the DHCP server). Additionally, if you have a problem with collecting machines like I do, invest in some kind of config management so it's easy to handle all the different things you're running.

Also, if you want to actually learn, I would strongly recommend against using Docker containers for everything. Besides being stuck with what the developers prefer, all the work of installing things is already done. Build things from source (optional), configure all the pieces yourself, work out all the dependencies and actually learn how things work. That's the fun, at least in my opinion. That's why I have yet another SBC with no OS to fiddle with this weekend: I'm looking to migrate from OpenWRT to real Linux so I can do everything myself instead of relying on OpenWRT's scripts.