There are at least, for those wanting a Linux or BSD based Motif fix: Enhanced Motif Window Manager https://fastestcode.org/emwm.html https://fastestcode.org/e

There are at least, for those wanting a Linux or BSD based Motif fix: Enhanced Motif Window Manager https://fastestcode.org/emwm.html https://fastestcode.org/emwm.html and the full-fledged CDE desktop that uses Motif also: https://sourceforge.net/projects/cdesktopenv/ https://sourceforge.net/projects/cdesktopenv/ (note that you want to firewall this somehow as the default settings on the background process ttdb can be a security hole)