I use open-source software every day, since November 2015. That was the year of Linux on the Desktop for me. I picked as my desktop environment Cinnamon.
I normally don’t use virtual desktops or “workspaces,” but on one laptop I was for a while. It was actually a KDE Plasma 5 installation, which reinforced my plans to stick to Cinnamon as my heavyweight DE. However, the KDE Plasma virtual workspaces worked fine, and provided all sorts of options for the window list and alt-tab switcher for listing windows across all the workspaces. Cinnamon did not have such an offering, so when I finally replaced KDE with Cinnamon on that workstation, I just reverted to my single-workspace workflow.
I told someone online (probably in the #korora channel at irc.freenode.net) that I was willing to pay money for Cinnamon to provide a window list option for displaying the windows from all workspaces. Well, as of October 2, I guess I owe myself $50.
Check out my merged pull request to Cinnamon! I added the feature, as a boolean setting, to the mainline Cinnamon window list applet. So eventually my option will be included in the Fedora Cinnamon build down the line. For the time being, though, I’m going to continue to use my separate applet that provides my feature.