Sawfish (the window manager formerly known as Sawmill) is an extensible window manager using a Lisp-based extension language. All window decorations are configurable and all user-interface policy is controlled through the language. Its aim is to manage windows in the most flexible and attractive manner possible. As such it does not implement desktop backgrounds, application docks, or other things that may be achieved through separate applications. Sawfish is mostly GNOME-compliant; almost all configuration may be made through a graphical interface.
CTWM is a highly-configurable window manager based on the classic TWM window manager. It supports xpms, multiple workspaces, advanced icon managment, animated icons and backgrounds, 3D titles and borders, etc. It offers rudimentary Gnome support and is backwards-compatible with TWM.