@pry grey productivity software in general, be it windows or unix. no frills design, low contrast but the ui elements with faux 3d were still pretty recognizable. shit just worked.
@pry CDE https://sourceforge.net/projects/cdesktopenv/ , Tcl/Tk without fancy theming, win2k, ...
most 90s-early 2000s era "professional" computer stuff had this look and was pretty usable compared to todays UI hell.