Themes for gtk2/gtk3 Gtk3.20 and up (But NOT gtk4).
Linux desktop and Ubuntu based derivatives like Zorin OS, Linux Mint and many other distributions. XFCE4, Cinnamon and Mate Desktop Environments.
Thank you for noticing one of the comments I made. I have to admit I have no idea what any of your deviations represent, but I'd like to know what they are. Thanks again from an old dude.
I was going to post something very similar to what you said in your comment. But since you said it, I did not need to, so liked your comment to show support.
My deviations are Desktop Themes for the Linux Operating System. Linux users can install them and apply them on their systems to customize their look. On Windows OS, this is usually called "skinning" and you can find a large number of themes for Windows on Stardocks Wincustomize Page. You must Buy the "Windowblinds" software on Windows to run them (On Linux of course, it is free and the functionality is Built In). Many Themes or Skins there must also be bought. Many are also free, though. Don5318 and Icebabee and vStyler and many others provide them.
I am Not On Windows and I do not use Windows... I only make the above reference so that Windows Users have a better idea of what a GTK Theme on Linux is. So you can more easily relate to what I am describing.
I find Customization of the Desktop Workbench to be essential. When you get to your computer and you log in to get some things done... if the desktop is dull, bland and boring, that is how you will feel while you work. But if seeing the desktop is something you Enjoy and Appreciate, then that sets the tone for the workday.