Workspace Matrix: provides a customizable n x m workspace grid, and a customizable pop-up that shows live preview of all workspaces and their windows (incl. e.g. video playing).
In combination, these two features allow me very quick overview of everything I have open, presented in an ordered fashion, allowing quick, keyboard-driven application change.
I’m not aware that the exact features of Workspace Matrix are reproduced by anything in any other DE.