xfdashboard - xfdashboard provides a GMONE shell dashboard like interface for use with the Xfce desktop.
Dexpot - If you don't have Dexpot yet, the new update makes it a must-have tool for Windows, adding a ton of features to your desktop that you never knew you wanted.
Window Maker - Window Maker is a free and open-source window manager for the X Window System
VirtuaWin - VirtuaWin is a virtual desktop manager for the Windows operating system (Win9x/ME/NT/Win2K/XP/Win2003/Vista/Win7/Win10). A virtual desktop manager lets you organize applications over several virtual desktops (also called 'workspaces').
GNUstep - GNUstep is a mature Framework, suited both for advanced GUI desktop applications as well as server...
Sysinternals Desktops - Desktops allows you to organize your applications on up to four virtual desktops.