I did something similar, but then I turned my pizero in a portable retro console lol.
Everything else is a nice to have, not essential
The arr family with a torrent client is great for feeding Jellyfin. If you are a developer, you can host your own shit there too. Game servers for playing with family and friends (so far Minecraft, Terraria, Project Zomboid, V Rising). I like to host a bunch of different telegram bots I wrote for fun. Discord bots are another interesting side. I also run some automation runners for helping out with testing, building and deploying my projects.
Focus on your needs and what you want to improve of your online life, there is probably a project you can self host for it.
I hope this doesn’t end up being a new crypto