Contexts - Switch between application windows effortlessly — with Fast Search, a better Command-Tab, a Sidebar or even a quick gesture. Free trial available.
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 !
Witch - Welcome to the world of W. i. t. c. h.
Skippy-XD - Skippy-XD is a full-screen task-switcher for X11.
Hyperswitch - HyperSwitch provides a compelling alternative to HyperDock for keyboard junkies. What's New
picom - A lightweight compositor for X11 (previously a compton fork).