Copylefted Software - Software development page of David Allen, which includes full source code for GTKeyboard, an application written for X using the GTK+ tookit, which allows physically disabled users to easily edit text files.
DDD - Data Display Debugger - A graphical front-end for command-line debuggers such as GDB, DBX, WDB, Ladebug, JDB, XDB, the Perl debugger, or the Python debugger.
Electric Sheep - A collaborative X screensaver for users with high bandwidth.
GTKeyboard - Site dedicated to distribution and information about GTKeyboard, an X11 application for disabled users.
ivtools - A suite of free X Window drawing editors for PostScript, TeX, and web graphics production, as well as an embeddable and extendable vector graphic shell.
John's World of XV - Multi-format image viewer with some editing capabilities.
Worker - A filemanager for X-Window. It should run on all POSIX-conforming systems. [Open source, GPL]
Xmmix - X11/Motif audio mixer - Premium audio mixer application for Linux (also works on other platforms running the 4Front Open Sound System (OSS) driver.
xosview - Displays dynamically-updated small bar charts representing CPU load, memory usage, swap usage, paging, disk activity and interrupts.
xpdf - A viewer for Portable Documentat Format (PDF) files.
XScreenSaver - A screen saver and locker for the X Window system.
xstep-shell - Use the Xstep-3.5.1 library and can be used in Linux shell scripts to ask for user input and to draw GUI's for the X Window system.
XtDesk - An X Window icon manager that runs under Linux and FreeBSD.
xvkbd - A virtual (graphical) keboard for X Window system.
x2vnc - An X program that will allow two machines to be controlled from the same keyboard and mouse. One machine must run X Window, the other can run X Window or Microsoft Windows.
xxkb - A simple GUI for XKB (X KeyBoard extension) and just sends commands to and accepts events from XKB. [Open source, Artistic license]