JWM is described as 'light-weight window manager for the X11 Window System. JWM is written in C and uses only Xlib at a minimum. Because of its small footprint, JWM makes a good window manager for older computers and less powerful systems, such as the' and is a Window Manager in the OS & Utilities category. There are more than 25 alternatives to JWM for a variety of platforms, including Linux, BSD, Mac, Windows and FreeBSD. The best alternative is i3, which is both free and Open Source. Other great apps like JWM are Openbox (Free, Open Source), awesome (Free, Open Source), Sway (Free, Open Source) and Xmonad (Free, Open Source).
Windawesome (pronounced - contrary to what you would expect from the way it is written - Windows-om, not Wind-awesome) is a highly customizable tiling/dynamic window manager with multi-monitor support for Windows, which works on top of explorer.exe and not as a shell replacement.
Heavily Inspired by i3wm. Wmderland aims to simplify the core functionalities of i3wm, and bundle in the essential features required for a modern but minimal Tiling Window Manager. Written in C++ using Xlib.
StumpWM is a tiling, keyboard driven X11 Window Manager written and scriptable in Common Lisp. StumpWM attempts to be customizable yet visually minimal. There are no window decorations, no icons, and no buttons.