transset-df is a heavily patched version of xorg's transset. It is used to set the transparency of windows in X with the xcomposite extension. It adds several command line options to make it easier to use directly, bound to hot keys in your window manager, or through scripts. These include the ability to select a window by window ID.
WnDO (formerly Fbdo) is a small suite of complementary tools for adding behavioral extensions to Gnome, Xfce, Fluxbox, and other window managers. WnDO offers a plugin platform for tweaking the desktop environment. It focuses on modifying behavior, rather than adding desktop widgets. It has minimal dependencies, other than Python. Included modules handle window alignment, simple window tiling, process management, wallpaper management, and custom keyboard shortcuts. Wallpaper management capabilities include per-workspace and randomly-selected wallpaper. It performs its own key grabbing in order to avoid interaction and conflict with the equivalent window manager facility. It requires CmDO.