That doesn't make the commands themselves "Unix commands", which would AFAIU, be described under the "Commands and Utilities" portion of the standard: http://www.opengroup.org/openbrand/register/cxm4.htm
The document containing these standards is not freely available online, but may be purchased: https://www2.opengroup.org/ogsys/jsp/publications/Publicatio...
Wikipedia lists a set of IEEE utilities which is pretty brief, and contains a number of largely obsolete standards (SCCS anyone?), comprising of 161 commands: https://en.wikipedia.org/wiki/List_of_Unix_utilities