awesome-status populates the awesome window manager's widgets. It features CPU usage, date/time, lm_sensors (CPU temperature, fan RPMs, etc.), memory/swap information, mpd information, network download/upload, sound card information (volume and outgoing level), and uptime information. An example commented configuration file is included.
X Persistent Remote Applications (xpra) is "screen for X". It lets you run applications remotely (like ordinary X or VNC), but unlike ordinary X, these applications are "persistent" if you lose your connection, or even if you want to switch to another computer. Also unlike VNC, they are ordinary applications on your desktop managed by your window manager, not trapped in a box.
dvtm brings the concept of tiling window management, popularized by X11-window managers like dwm, to the console. As a console window manager, it tries to make it easy to work with multiple console based programs like vim, mutt, cmus, or irssi. dvtm is intended to be used where X11 isn't available or over SSH. In conjunction with dtach, it can be seen as a lightweight alternative to GNU screen.
Perl OS is a program that provides an easy interface to run Perl/Tk programs. It was also created to be an easy working environment, complete with a text editor, paint program, and more. It comes with several programs, along with a utility to add many more which can be found on the Internet. From the outside, Perl OS looks like a simple operating system. But inside, it is a powerful system for working with Perl and Tk.
xlayout is a terminal-based utility to get and set information about X11 windows and the pointer. It's designed to be easily integrated into bash shell scripts and takes advantage of the X11 protocol to allow it to access remote X11 desktops. With the aid of the libease library, xlayout provides the ability to smoothly ease the windows and pointer into position.
The wmctrl program is a command line tool to interact with an EWMH/NetWM-compatible X Window Manager. It provides command line access to almost all the features defined in the EWMH specification. It's possible to, for example, obtain information about the window manager, get a detailed list of desktops and managed windows, switch and resize desktops, change the number of desktops, make windows full-screen, always-above, or sticky, and activate, close, move, resize, maximize, and minimize them. The command line access makes it easy to automate these tasks and execute them from any application that is able to run a command in response to some event.