Flwm is an X window manager designed to be user friendly and use the absolute minimum amount of screen real estate. It has no icons, using a pop-up menu to select hidden or new windows, and sideways titlebars. Flwm is also designed to achieve Gnome, KDE, and Motif compatibility simultaneously and has also been tested with many SGI programs that normally require 4DWM.
FVWM is a multiple large virtual desktop window manager originally derived from twm. FVWM is intended to have a small memory footprint and a rich feature set, be extremely customizable and extendable and have a high degree of Motif mwm compatibility. FVWM is highly extensible through its module interface.
FvwmPartition is a FVWM2 module that allows the user to build a structure of panes in a fairly arbitrary manner. Windows can be attached to these panes and manipulated together by dragging the bars that separate the panes. Windows in a specific pane can selected by tapping the labels on the parent bar or moved by drag-and-dropping the labels.
Ion is a tiling (no overlapping windows) window manager that also has PWM-style tabbed frames which can contain multiple client windows. These features help to keep windows organized and to switch quickly between them. Ion was designed primarily as an efficient and unobtrusive window manager for users who prefer the keyboard.