HyperKeys - Unleash the power of your keyboard by letting you bind ANY action to a shortcut. It's open-source and fully extendable. You can code you own actions or use one from the community !
Charmstone - The quicker switcher launcher for macOS
Skippy-XD - Skippy-XD is a full-screen task-switcher for X11.
SwitchGlass - Customizable app switcher for Mac
VistaSwitcher - VistaSwitcher is an elegant and powerful task management utility for Windows OS.
Witch - Welcome to the world of W. i. t. c. h.