Letter: X
- x11-ssh-askpass - A passphrase dialog for X and not only for OpenSSH
- x2vnc - Dual screen hack for VNC
- x3270 - An X Window System based IBM 3278/3279 terminal emulator
- xaos - A fast, portable real-time interactive fractal zoomer
- xar - The eXtensible ARchiver
- xarchiver - Archive manager for Xfce
- xarchon - Arcade board game
- xawtv - TV applications for video4linux compliant devices
- xbae - Motif matrix, caption and text input widgets
- xbase - XBase compatible database library and tools
- xbindkeys - Binds keys or mouse buttons to shell commands under X.
- xbiso - ISO extraction utility for xdvdfs images
- xblast - Lay bombs and Blast the other players of the field (SDL version)
- xblast-data - Data files for the game xblast
- xboard - An X Window System graphical chessboard
- xbsql - A SQL wrapper for xbase
- xca - Graphical X.509 certificate management tool
- xchat-gnome - GNOME front-end to xchat
- xchm - A GUI front-end to CHMlib
- xcircuit - Electronic circuit schematic drawing program
- xclip - Command line clipboard grabber
- xcompmgr - X11 composite manager
- xdaliclock - A clock for the X Window System
- xdesktopwaves - Simulation of water waves on the X Window System desktop
- xdg-utils - Basic desktop integration functions
- xdms - Extracts Amiga DMS archives
- xdrawchem - 2D chemical structures drawing tool
- xemacs - Different version of Emacs
- xemacs-packages-base - Base lisp packages for XEmacs
- xemacs-packages-extra - Collection of XEmacs lisp packages
- xerces-c - Validating XML Parser
- xeuphoric - An X based ORIC emulator
- xfce-mcs-manager - Multi channel settings manager
- xfce-mcs-plugins - Plugins for multi channel settings manager
- xfce-utils - Utilities for the Xfce Desktop Environment
- 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-dev-tools - Xfce developer tools
- xfce4-dict-plugin - A Xfce panel plugin to query a Dict server
- xfce4-diskperf-plugin - Disk performance plugin for the Xfce panel
- xfce4-eyes-plugin - Eyes 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-mailwatch-plugin - Mail Watcher plugin for the Xfce panel
- xfce4-minicmd-plugin - Mini command-line plugin for the Xfce panel
- xfce4-mixer - Volume control plugin for the Xfce 4 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-panel - Next generation panel for Xfce
- xfce4-places-plugin - Places menu 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-session - Xfce session manager
- xfce4-smartbookmark-plugin - Smart bookmarks for the Xfce panel
- xfce4-systemload-plugin - Systemload monitor for the Xfce panel
- xfce4-taskmanager - Taskmanager for the Xfce desktop environment
- xfce4-timer-plugin - Timer for the Xfce panel
- xfce4-verve-plugin - A comfortable command line plugin for the Xfce panel
- xfce4-volstatus-icon - System tray icon to easily eject removable devices
- 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-xfapplet-plugin - A plugin to use gnome-panel based applets inside the Xfce4 panel
- xfce4-xkb-plugin - XKB layout switcher for the Xfce panel
- xfce4-xmms-plugin - XMMS plugin for the Xfce panel
- xfdesktop - Desktop manager for the XFce Desktop Environment
- xforms - XForms toolkit library
- xfprint - Print dialog and printer manager for Xfce 4
- xfsdump - Administrative utilities for the XFS filesystem
- xfwm4 - Next generation window manager for Xfce
- xfwm4-themes - Additional themes for xfwm4
- xgalaxy - Galaxian / Galaga like game with powerups
- xgrav - A simple physics simulation for a large number of particles
- xine-lib - Xine library
- xine-plugin - Media plugin for mozilla compatible browsers using libxine backend
- xkeycaps - Graphical front end to xmodmap
- xl2tpd - Layer 2 Tunnelling Protocol Daemon (RFC 2661)
- xlhtml - Excel 95/97 and PowerPoint to HTML converter
- xlockmore - Screen lock and screen saver
- xmldiff - Tree to tree correction between XML documents
- xmlindent - XML stream reformatter
- xmlrpc-c - A lightweight RPC library based on XML and HTTP
- xmlstarlet - Command Line XML Toolkit
- xmms - The X MultiMedia System, a media player
- xmms-acme - XMMS plugin to use special multimedia keys in GNOME or through acme
- xmms-adplug - An XMMS plugin for AdLib (OPL2) music built on AdPlug
- xmms-alarm - Plugin for using XMMS as an alarm clock
- xmms-arts - X MultiMedia System output plugin for the aRts sound system
- xmms-cdread - Digital audio CD input plugin for XMMS
- xmms-crossfade - Audio crossfade plugin for XMMS
- xmms-flac - XMMS plugin needed to play FLAC (Free Lossless Audio Codec) files
- xmms-lirc - X MultiMedia System control plugin to use infrared devices
- xmms-modplug - Modplug Plugin for XMMS
- xmms-musepack - X MultiMedia System input plugin to play musepack (mpc) files
- xmms-scrobbler - Audioscrobbler plugin for XMMS
- xmms-sid - SIDPlay input plugin for X MultiMedia System (XMMS)
- xmms-skins - Skins for the X MultiMedia System
- xmms-speex - X MultiMedia System input plugin to play speex files
- xmoto - Challenging 2D Motocross Platform Game
- xmoto-edit - Challenging 2D Motocross Platform Game - Level Editor
- xoo - Xoo is a graphical wrapper around xnest
- xosd - On-screen display library for X
- xpa - The XPA messaging system
- xpdf - A PDF file viewer for the X Window System
- xpilot-ng - Multiplayer space arcade game
- xplanet - Render a planetary image into an X window
- xprobe2 - Xprobe2 is an active operating system fingerprinting tool
- xsc - A clone of the old vector graphics video game Star Castle
- xscorch - A Scorched Earth clone
- xscreensaver - X screen saver and locker
- xsp - A small web server that hosts ASP.NET
- xsupplicant - Open Source Implementation of IEEE 802.1x
- xtide - Calculate tide all over the world
- xu4 - Ultima IV recreated
- xvattr - Utility for getting and setting Xv attributes
- xwnc - Mix of Xvnc and XDarwin with improved protocol
- xwrits - Reminds you take wrist breaks
- xzgv - A GTK+/Imlib-based picture viewer for X