Sway is a tiling Wayland compositor and a drop-in replacement for the i3 window manager for X11. It works with your existing i3 configuration and supports most of i3's features, plus a few extras.
A dynamic window manager for X11 written with Node.js
Razor-qt is an advanced, easy-to-use, and fast desktop environment based on Qt technologies. It has been tailored for users who value simplicity, speed, and an intuitive interface. Unlike most desktop environments, Razor-qt also works fine with weak machines.