In case you don't know yet, there is a project that tries to bring the NeXTSTEP look and feel to Linux:

https://github.com/trunkmaster/nextspace

Interesting, this seems to have been around for quite a while, though not as long as AfterStep and Window Maker. I wonder why the author decided to write their own version instead of helping out with one of those projects.

I wish that all of these sort of efforts would be folded into GNUstep:

gnustep.org

and that we would arrive at something useful and easily installed and widely accepted.

There was WindowMaker for a while too, just a window manager.