I am just wondering, are there any more hidden functions in excel that you are aware of other than the ones listed below..well I am talking about version 2007 or below
There seems to be some confusion here ; if you mean Excel 2007 and below as you have posted , then AGGREGATE does not fit in.
If you mean Excel 2010 and above , since AGGREGATE is not available in Excel 2007 and below , then AGGREGATE is a well-documented function , unlike the other two. DATEDIF is undocumented , while EVALUATE is not just undocumented but even obsolete. And like EVALUATE there is a complete list of Excel 4.0 macro functions which are still available in later versions of Excel.
By undocumented I mean not documented in the official Excel help.
By obsolete I mean unsupported by Microsoft.
See the following links for more information on Excel 4.0 macro functions :