Letter: X
- xbase - XBase compatible database library and tools
- xbindkeys - Binds keys or mouse buttons to shell commands under X.
- xbsql - A SQL wrapper for xbase
- xca - Graphical X.509 certificate management tool
- xdaliclock - A clock for the X Window System
- xdesktopwaves - Simulation of water waves on the X Window System desktop
- xfcalendar - Time-managing application for Xfce4
- xfce4-appfinder - Appfinder for the Xfce4 Desktop Environment
- xfce4-battery-plugin - Battery monitor for the Xfce panel
- xfce4-clipman-plugin - Clipboard manager plugin for the Xfce panel
- xfce4-cpugraph-plugin - CPU monitor for the Xfce panel
- xfce4-datetime-plugin - Date/time plugin for the Xfce panel
- xfce4-diskperf-plugin - Disk performance plugin for the Xfce panel
- xfce4-fsguard-plugin - Filesystem-Guard plugin for the Xfce panel
- xfce4-genmon-plugin - Generic monitor plugin for the Xfce panel
- xfce4-icon-theme - Icons for Xfce
- xfce4-minicmd-plugin - Mini command-line plugin for the Xfce panel
- xfce4-mixer - Volume control plugin for the Xfce 4 panel
- xfce4-modemlights-plugin - Modemlights for the XFCE panel
- xfce4-mount-plugin - Mount/unmount utility for the Xfce panel
- xfce4-netload-plugin - Network-load monitor for the Xfce panel
- xfce4-notes-plugin - Notes plugin for the Xfce panel
- xfce4-quicklauncher-plugin - Quicklauncher plugin for the Xfce panel
- xfce4-screenshooter-plugin - Screenshot utility for the Xfce panel
- xfce4-sensors-plugin - Sensors plugin for the Xfce panel
- xfce4-showdesktop-plugin - Show-Desktop plugin for the Xfce panel
- xfce4-systemload-plugin - Systemload monitor for the Xfce panel
- xfce4-taskbar-plugin - Tasklist plugin for the Xfce panel
- xfce4-taskmanager - Taskmanager for the Xfce desktop environment
- xfce4-toys - Various tools for Xfce4
- xfce4-trigger-launcher - A panel plugin acting as a launcher with two states
- xfce4-wavelan-plugin - WaveLAN plugin for the Xfce panel
- xfce4-weather-plugin - Weather plugin for the Xfce panel
- xfce4-websearch-plugin - Websearch plugin from the XFCE panel
- xfce4-windowlist-plugin - Windowlist plugin for the Xfce panel
- xfce4-xkb-plugin - XKB layout switcher for the Xfce panel
- xforms - An X11 toolkit library.
- xkeycaps - Graphical front end to xmodmap
- xlhtml - Excel 95/97 and PowerPoint to HTML converter
- xlockmore - Screen lock and screen saver
- xmlindent - A XML stream reformatter
- xmlstarlet - Command Line XML Toolkit
- xmms-acme - XMMS plugin to use special multimedia keys in GNOME or through acme
- xmms-alarm - xmms General plugin for using xmms as an alarm clock
- xmms-cdread - Digital audio CD input plugin for XMMS
- xmms-crossfade - A crossfade output plugin for XMMS
- xmms-lirc - X MultiMedia System control plugin to use infrared devices
- xmms-modplug - Modplug Plugin for XMMS
- xmms-sid - SIDPlay input plugin for X MultiMedia System (XMMS)
- xmms-speex - X MultiMedia System input plugin to play speex files
- xosd - On-screen display library for X
- xplanet - Render a planetary image into an X window
- xprobe2 - Xprobe2 is an active operating system fingerprinting tool
- xscorch - A Scorched Earth clone
- xsupplicant - Open Source Implementation of IEEE 802.1x
- xtide - A program for calculating tide all over the world
- xvattr - Utility for getting and setting Xv attributes