What else should I host in this (not tilde) server?

Now that I got the Raspberry Pi out there and doing some work with the static site, I'm now left wondering what else could I do with it in terms of other services besides websites that I could host on it, hopefully accessible outside of the browser.

I have a previous list of things I have considered, way before even owning a Pi, though their degrees of complexity vary, and some other stuff I recently considered. For example:

XMPP server: with Prosody and Let's Encrypt, I think the process is made much more simple. I had deployed it once way back in 2015 (or 2016?) for a brief moment, but since the hardware was difficult to maintain (an overheating netbook connected via WiFi to the router) I ended up dropping the project. Relatively easy, I think.
IRC server: can't see how much different than XMPP this would be in terms of install difficulty, but I have zero experience on it. I hear it's not too resource-heavy either, another good point, but the lack of federation of the protocol is a little discouraging.
Gitweb server: I already use this Pi as my local git server for small projects and notes, but maybe I could put a public (or semi public?) view or mirror of my main ones myself. Gogs, I guess? Gitea? At any rate yay for self-hosting!
Peertube instance: a Fiber connection should make it alright in terms of speed, but I'm not sure the hardware would be enough. Seems to me that should be pretty CPU-intensive, but does anybody know?
Fediverse instance: I think Pleroma used to advertise itself as "light enough to run on a Raspberry Pi" back when that meant the Raspberry Pi Model 2B with 512MB RAM. Can my Pi survive the intensity of bandwidth usage and storage use (images, videos, etc)? Good question!
A self-developed hacky thing: temporary file storage (like tmp.sh)? URL shortening service? Some program I'm going to write myself and then publish the source as an exercise.

What else do you think could be an interesting sevice to host? Let me know on Mastodon!