The xlibs from freedesktop.org that have been packaged
marked with plus sign:

xlibs - meta package to help build all of the libraries                  
+ compositeext
+ libXcomposite
+ damageext - X Damage extension headers and specification
+ fixesext - X Fixes extension headers and specification
+ libICE - Inter Client Exchange library
+ randrext - X Resize and Rotate extension headers
+ render - X Render extension headers
+ resourceext - X Resource usage extension headers
+ libSM - Session Management library
+ libX11 - Base X libs
+ xextensions - various extension headers
+ libXres - X Resource usage library
+ libXau - Authorization Protocol for X                                       
+ libXcursor - Client-side cursor loading library                             
+ libXdamage - X Damage extension library                                     
Xdmcp - X Display Manager Control Protocol library                       
+ libXext - X Extension library                                               
+ libXfixes - X Fixes extension library                                       
+ libXfont - X font libary (used by the X server)                             
+ Xft - X FreeType library. Client-side fonts with FreeType                
+ libXi - X Input extension library                                           
+ xproto - X protocol and ancilary headers                                 
+ libXrandr - X Resize and Rotate extension library                           
+ libXrender - X Render extension library                                     
+ xtrans - network API translation layer to insulate X applications and    
	libraries from OS network vageries
+ (not finished but imported) libXv
+ libXt (my source)

others needed:

libXmu
libXaw

also need to consider that some Xlibs may use:
X uses
/usr/share/X11/locale/locale.alias
/usr/share/X11/locale/locale.dir
/usr/lib/X11/app-defaults/app-name-here