A number of style options have been added to the LaTeX system over the years. Some of these options have very good documentation, while others have virtually none. As far as I know, these are the options for the standard LaTeX 2e system that work on our setup. There may be some LaTeX 2.09 style options that will also work as packages, but this is not generally guaranteed.
The list of known document classes includes
The list of known document styles includes