The problem is that the COM automation libraries are (mainly) associated with a bit of installed software, such as Internet Explorer or AutoIT. The documentation for the interfaces will be supplied by the individual software house. Sometimes no documentation is available to the public, because the object is not intended to be used that way. API documentation that is available may be copyrighted or otherwise protected.

This is why it may be easier to start with the typelib viewer to find some interesting interfaces, then search the web for available documentation.

The "COM Automation Resources" sticky topic in this forum has a few links which might be useful.

If you do manage to find a categorised list be sure to come back and let us know!