Utility libraries for XC Binding
http://xcb.freedesktop.org

X Rendering Extension client library

X.Org X servers

rdesktop is used to connect to windows terminal servers
http://www.rdesktop.org/

X11 keyboard UI presentation library

X11 toolkit intrinsics library

X11 Session Management library

X11 Inter-Client Exchange library

X11 Resource extension wire protocol

X11 Big Requests extension wire protocol

X11 XC-Miscellaneous extension wire protocol

X11 Render extension wire protocol

X11 RandR extension wire protocol

X keyboard configuration files
http://www.freedesktop.org/wiki/Software/XKeyboardConfig

The internationalization tool collection
http://freedesktop.org/wiki/Software/intltool

compile XKB keyboard description

X11 keyboard file manipulation library

X11 XFree86 miscellaneous extension library

X11 XFree86-Miscellaneous extension wire protocol

X11 OpenGL extension wire protocol

X11 DRI protocol

X11 font rasterisation library

X11 font extension wire protocol

X11 font encoding library

X11 damaged region extension library

X11 Damage extension wire protocol

X11 miscellaneous 'fixes' extension library
http://xorg.freedesktop.org/

X11 Fixes extension wire protocol
http://xorg.freedesktop.org/

Userspace interface to kernel DRM services
http://dri.freedesktop.org/

X11 XFree86 video mode extension library
http://xorg.freedesktop.org/

X11 miscellaneous extensions library