Witch - Welcome to the world of W. i. t. c. h.
Xfce - Xfce is a lightweight desktop environment for UNIX-like operating systems. It aims to be fast and low on system resources, while still being visually appealing and user friendly.
Hyperswitch - HyperSwitch provides a compelling alternative to HyperDock for keyboard junkies. What's New
LXDE - Why will you like it? Less resource needs. You can use it on your less-pricey embedded board or salvaged computer. Component-based design. Don't want something in LXDE, or you don't want to use LXDE but only part of it?
Contexts - Switch between application windows effortlessly — with Fast Search, a better Command-Tab, a Sidebar or even a quick gesture. Free trial available.
KDE Plasma Desktop - Plasma Workspaces is the umbrella term for all graphical environments provided by KDE.