Personally, I run my self-hosting setup using an old laptop I had lying around, and if you have an device you no longer use, it’s a really good option hardware-wise!

I would recommend Debian, it’s stable and it works well enough. I’ve heard Yunohost being a nice option, but I was unable to get it to install. Maybe my particular hardware didn’t play nice with it, or perhaps I just did something wrong in the install process. The majority of services I’m running use docker, since it’s convenient and automatically updates itself.

As for the stuff that’s nice to run, you of course need file storage. I use Nextcloud, but it was a pain to set up (if you need any help, I would guide you towards LearnLinuxTV, who has great videos on setting up NextCloud). In hindsight, I probably should have installed something lighter weight since I don’t use any of Nextcloud’s extra features, but it works and many apps gives you options to use Nextcloud sync which is convenient. I also use Syncthing for syncing my notes and other bits between my devices.

I would also recommend Immich for photo hosting. It works really well and the mobile app is fantastic on both Android and iOS (I use the former now and the latter in the past). It doesn’t have a client for desktop though, so that could be a dealbreaker.

Forgejo is really good, I use mine for local project backups, with Codeberg acting as the cloud backup. I don’t have that much more to say, it works well!

Running a Minecraft server is also very fun. I use Paper to run a vanilla survival server that’s just for me and my siblings, and I have the plugins Geyser and Floodgate so that the littlest can play with me on their tablet, which runs Bedrock rather than Java Edition.

I don’t currently run this myself, but Pi-hole seems amazing, being able to block ads and trackers on the network! I will have to try that out in the future…

If you have (definitely legally obtained) media, like movies, shows, anime, etc., Jelkyfin seems like a great option. Lots of people rip content from DVDs and Blu-rays that they have bought.

I also use Radicale, a CalDAV calendar service. It can sync all the events I have in the future between all my devices, and it’s the first I have used that syncs properly among all my devices. Previously, I used two local calendars, adding the event on the device where it is most appropriate (for instance, school stuff on my laptop and social gatherings on my phone), and it was a lot of hassle. Having one calendar between all my devices is very nice indeed. On Android, I found Etar to be the most functional client, while on desktop (currently running EndeavourOS, previously Fedora), Thunderbird is probably the best option and the one I use. If you use GNOME, you could get by with their calendar app that is minimal+, and on KDE, you have KOrganiser that has a bazillion different features crammed into the interface.

One more thing, if you have spare resources, you can always run BOINC or similar in the background. Lending some of your unused compute helps out science :D I personally run Asteroids@home and Milkyway@home since I’m interested in astronomy and such, but there are BOINC projects relating to medicine, biology, and other fields of science too!