Orion is a window manager for the X11 windowing system. It is written in Scheme and accesses Xlib via the scx library for scsh. It is in fact a family of window managers that can be nested. This enables great flexibility and efficient handling of X11 applications. It currently comes with four child window managers: a conventional moving window manager, a window manager for stacking windows in a frame, a window manager for splitting windows horizontally, and vertically and a work space manager. It also supports saving the window manager layout and programmatic configuration.
libAfterImage is an image import, storage, manipulation, and output library for X. It features support for antialiased, TrueTypei, and X text, a 128-bit internal graphics engine, in-memory RLE image compression, high quality image scaling/flipping/blending, multipoint linear gradients, superior quality image output on X drawables, and much more.
wmsystray provides a system tray compatible with freedesktop.org's System Tray Protocol specification. Basically, it serves as a system tray that allows other programs to show icons in it. For example, if you enable GAIM's System Tray Icon plugin, wmsystray will display GAIM's systray icon. Its intended use is as a Window Maker dock app, though it will run in other window managers as well.
MIcroscopic Window Manager (MIWM) is a fast, small, minimalist, and extremely reliable window manager. It is designed to do the job very simply and unobtrusively, without constraining power users. It features optional auto-tiling, desktop cleanup, a user-defined root menu, optional previewing of hidden windows, variable numbers of virtual desktops, and configurable window behavior. It includes a simple, very effective memory management utility for leak detection.
xmonad is a tiling window manager for X. Windows are arranged automatically to tile the screen without gaps or overlap, maximising screen use. Window manager features are accessible from the keyboard; a mouse is optional. xmonad is extensible in Haskell, allowing for powerful customisation. Custom layout algorithms, key bindings, and other extensions may be written by the user in config files. Layouts are applied dynamically, and different layouts may be used on each workspace. Xinerama is fully supported, allowing windows to be tiled on several physical screens.