While putting together the examples that use LINQ to XML to query Open XML documents, I needed to have a finite list of the XML content types. To determine whether a particular part contains XML, the correct approach is to see if the ContentType for the part is one of a specific list of content types. These content types are listed in Part 1 of the Open XML specification, however, they are not really in a format that is accessible programmatically. So, I spent a little while going through Part 1, copying and pasting the content types. Then I used LINQ, and LINQ to XML to spit out the content types as an XML document. I believe that this list is complete, but would not be surprised if there were errors. Please let me know if you find any missing content types, or errors. Here is the XML content types document.