There are dozens and dozens of new operating systems listed here.
Most are experiments -- what you might call hobby projects -- but
there are some interesting ideas implemented among them.
The title is arguably a bit baity. I have not been keeping that much up with now now. I guess all the OSes that are out there right now have been out for at least a decade now, indeed. Redox, Haiku, Serenity, the Assembly ones, Qubes (is that really an OS, though?)...
There are dozens and dozens of new operating systems listed here. Most are experiments -- what you might call hobby projects -- but there are some interesting ideas implemented among them.