XFree86 and various window managers (back in the early 90s there were no free/open source desktop environments yet; KDE (1996) was the first I think, or at the very least earlier than Gnome.
As a point of historical interest, XFCE actually holds the title of the oldest extant DE project; it beat KDE to first release by about a year.
KDE was also famously not entirely open source when it was founded (Qt was closed until v2), which is why GNOME was founded (initially by the GNU Project) exactly for this reason.
As a point of historical interest, XFCE actually holds the title of the oldest extant DE project; it beat KDE to first release by about a year.
KDE was also famously not entirely open source when it was founded (Qt was closed until v2), which is why GNOME was founded (initially by the GNU Project) exactly for this reason.