Kando will be a pie menu for the desktop. It will be highly customizable and will allow you to create your own menus and actions. For instance, you can use it to control your music player, to open your favorite websites or to simulate shortcuts.
It will be available for Windows, Linux and maybe macOS.
Since Kando is still in early development, it might be a good idea to look at the Gnome Extension Fly-Pie. It’s from the same developer and it looks like Kando will be similar.