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.
Wayfire - Wayland compositor with 3d effects.
LXQt - The LXQt team is proud to announce the release of qtermwidget and qterminal, both in version 0. 8. 0. Read more..
i3 - A dynamic tiling window manager designed for X11, inspired by wmii, and written in C.
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?
KDE Plasma Desktop - Plasma Workspaces is the umbrella term for all graphical environments provided by KDE.