Where can I find a list of all of the document types in CORE and infoAdvantage?

You will want to enter DTYP in the Jump to field in CORE to see a list of document types.  There you will also see the document type name, category, and category name.  To see what document types are in infoAdvantage, you can choose a report like GA-999 and refresh the list on the document code to get a full list of the all the document types.