x10mp3 is a plugin for XMMS to control it using X10's Mp3Remote, which comes with Mp3Anywhere, Mp3Anywhere 2000, or DVDAnywhere. It has all the functionality of X10's BOOM2000 software for Windows, plus other handy features like muting, skipping around inside tracks, and balance control.
x11vis is a visual and interactive tool for debugging X11 clients. Unlike other tools such as xtrace, it displays human readable IDs on all requests, no matter at which point in time the information becomes available. To help you cope with large amounts of data, it displays only the most important information by default, automatically folds sequences of boring requests, allows you to filter by packet type or client, and provides markers for navigation. Instead of assigning a number to each connection, it displays the command line with which that client was started.
x2search is a crawler based on machine learning algorithms that finds pages and documents that are similar to given positive and different to given negative examples. The learned classifiers can be exported and saved for later reuse. It features multiple settings for searching by domain/server, etc. and has a plug-in mechanism for adding document types to be searched.
x509watch is a simple command line application that can be used to list soon expiring or already expired X.509 certificates, such as SSL certificates. All certificates are searched by default in the standard PKI directory, but any other directory can be specified as a parameter. Only Base64 encoded DER and PEM X.509 certificates are supported.
x9wm is a clone or fork of the 9wm and w9wm X window managers. It is a light alternative for the Mac OS X desktop. All of its source code is contained in a single file. It supports an alterate red colored cursor. It is very light on resources, quite fast, very simple, and easy for long programming, editing, or Web work sessions. You can blend it with Nitrogen and Wbar to create a simple but elegant interface without iconic or stylistic clutter. It does not decorate windows with borders, and it is modal, controlled with the mouse.
xAutoClick is an autoclicker application that enables you to automatically click the left mouse button. It is designed to reduce strain on the wrist muscles caused by repetitive mouse clicking, which can lead to serious injury or impairment (RSI, Carpal Tunnel Syndrome, et cetera). By specifying the interval, a random factor and the number of times to click, the program simulates natural clicking.