Autodesk now have a web page where they list standard out of the box (OOTB) keyboard shortcuts:
http://www.autodesk.com/shortcuts/revit
The list below is altered from the standard OOTB shortcuts.
Mainly twin letter commands have been added - AA = align, CC=copy, MM=move, TT=text etc.
NOTE: This list is from an earlier Revit version, and is not comprehensive.