I've got some projects that are fun to get up and running for sure.
Kasm Workspaces - Containerized apps fully accesible through a browser. Think Firefox, Discord, or even a full Linux distro.
Games on Whale - Turn your server into a remote emulation station. You can use Moonlight to remote into your system and run all kinds of emulators. Requires a lot of config to get working though. (Look for Wolf, it's the improved version of Gamesonwhale"
Stable-diffusion - if you've spare GPU power, use it to generate some AI shit. Fun as fuck to mess around with.
speedtest-tracker - Love my metrics. Keeps track of your up/down rates.
AudioBookShelf - my go to Audiobook player. good phone apps too.