I make the specification of non-linux because otherwise this would just become a thread full of obscure distros that do the same thing as a million other distros.
Some lesser known OSs:
- AROS - based on Amiga OS, has some derivatives like IcarOS and MorphOS
- Haiku - based on BeOS
- Redox - Unix-like, made in Rust (might technically count as linux?)
- Serenity - Unix-like, very late 90s look and feel
- Kolibri - Tiny OS, the image is ~44MB. It also has a smaller version that fits in a single floppy.
- PhantomOS - When 3 Russians decide to turn everything about a typical OS upside down.
GNU Hurd and Plan9.
Gnu Guix is working on HURD integration.
I am on Guix, so I’m really excited to switch the kernel. But it won’t be available at least for a decade. Or maybe more.
I feel like HURD is the generational starship of operating systems. Will never be completed in my lifetime but eventually my great great grand children may some day use it.