xcplay is an ncurses interface to XMMS. The UI is a clone of cplay, but using XMMS as a backend instead of console players, running either as a GUI-stripped daemon or on a virtual X server (Xvfb). Advantages over cplay include seeking for many more formats, detachment, unlimited instances, and console player independence.
xdot.py is an interactive viewer for graphs written in Graphviz's dot language. It internally uses the graphviz's xdot output format as an intermediate format and PyGTK and Cairo for rendering. It can be used either as a standalone application from command line or as a library embedded in a Python application.
xfburn is easy to use burning software for the Xfce desktop environment (but will work with others). It uses libburn and libisofs as a backend. ISO files can be burned, data composition created, discs blanked, and DVD-RW media formatted and deformatted. Common burning software features not yet implemented are audio CD creation and disc copying.
xfigchart.pl is a quick and easy way to create bar charts. It uses a commandline interface and takes data values as a table from stdin and writes an XFig file to stdout. Postprocessing of the bar charts is done manually using the free vector drawing tool XFig, with which it is possible to create very complex diagrams mixed with other graphics components in a short time and to use a variety of export filters (PostScript, LaTeX, PNG, etc.).