i3 - A dynamic tiling window manager designed for X11, inspired by wmii, and written in C.
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.
Fluxbox - Fluxbox is a window manager for X that was based on the Blackbox 0.61.1 code.
KDE Plasma Desktop - Plasma Workspaces is the umbrella term for all graphical environments provided by KDE.
Openbox - Openbox is a highly configurable, next generation window manager with extensive standards support.
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?