Kittens is an application container that can embed X applications and steal them from your window manager in order to provide advanced window management options to any window manager. It can tab windows together, split to show them vertically side by side, and allow applications and splits to be resized with the mouse or keyboard. It works in environments such as GNOME, KDE, and XFCE. Kittens is also ideal for managing applications without having to use a mouse.
libNUI is a hardware accelerated GUI framework that makes it possible to build rich multi-platform applications based on 3D rendered dynamic layouts. Interfaces are built as a composition of widgets and behaviors, and the framework handles positioning, resizing, anchoring, and texture stretching. Objects are connected with synchronous events and delegates for mono-threaded communication, or asynchronous notifications and message queues are used for multi-threaded applications. It also supports strings (including Unicode), paths, files, data streams, fonts, threads, critical sections, audio buffer rendering, and more.
Libcvautomation is a GUI automation and testing tool based on image recognition and response. This program was designed as a direct replacement for Sikuli and Xpresser. Each solution had large problems with crashing, and both refused to function on Red Hat Linux and Ubuntu 12.04. The author really liked the way each of these programs approached GUI automation, but they simply didn't work. As such, a simple library was designed to integrate OpenCV and XTest, which can be used by BASH to drive GUI testing and automation, and works on both new and old Linux distributions.
netwmpager is an enhanced version of the original netwmpager-1.11 program written around 2005 by Timo Hirvonen. It should be compliant with the EWMH (or NetWM) specifications. This version implements virtual desktops split into different viewports, into different desks, or both, while the earlier version only supported desks. As a consequence, netwmpager-2 should work with most window managers; it has been tested especially with compiz, fluxbox, and fvwm. It also has many parametrizable features, and it implements a convenient zoom.
Notion is a tiling tabbed window manager for X. This means the screen can be freely divided into tiles that contain the client windows. Multiple client windows can occupy the same tile; in that case they will be tabbed, much like browser tabs. This way, windows will not overlap and it becomes easier to manage your screen real estate. Its functionality can be configured and even extended with Lua scripts. Various scripts are available, such as for NetWM features and multihead support.
subtle is a grid-based manual tiling window manager with a strong focus on easy but customizable look and feel. In comparison to other tiling window managers, subtle has no automatic tiling of the screen size in any way. Instead, windows are arranged according to positions inside of a grid. These positions are called gravities.