John, there is no list of attributes or #directives that exists as documentation.
There is a good list of #directives, however, in the form of an outline.
It might not be 100 percent complete, but when I was developing the CMS, I put an initialization for every directive in that file, and they override the initializations in the software. But there still could be a few that only the software knows about.
There are docs for many of the attributes scattered around the Fargo docs. It would be nice to see them all come together on one page, perhaps on a community-edited wiki.