Here's a spreadsheet of the elements for each of the "common" (Userland 0.91, 0.92, 2.0, and RSS 1.0) RSS formats out there. This spreadsheet is my personal reference for the squaggle schemas and element lists. At the moment it's an evil Microsoft Excel file (generated with OpenOffice; I'll convert it to something a bit more sane later on. At the moment only the RSS 0.91 and 0.92 (again, Userland) are complete.