Guix, slackware, void, PCLinuxOS, vanilla debian

Non linux: FreeBSD, OpenBSD, NetBSD, HaikuOS

arch

Something simple to the tune of pop!_os and linux mint - Manjaro

No fuss, just great experience and freedom - Debian

If you want something solid you can depend on, especially when you forget to update and don’t really need the newest features, Debian will carry that need. I love that distro and it’s good to have installed as a backup tool even if you don’t think it’s a good main choice for you.

if you want an interesting distro to mess around with, you can try Guix or NixOS