This is the first post I wrote on the topic of Polyhedral Pantheons, but the Polyhedral Pantheons Hall of Fame page is a better starting point. It has links to pretty much everything on my site regarding Polyhedral Pantheons, and even some on other sites.
I am shamelessly stealing the idea for this from The Rose of the Prophet trilogy by Margaret Weis and Tracy Hickman.
The pantheon is designed somewhat using an icosahedron (a d20). There are twenty gods, each defined by three attributes or primary influences (which color the personality and goals of the god). Good, Evil, Love, War, and so on.
This seems almost made for a pantheon design system using clerical domains, doesn’t it?
(It could make use of portfolios instead, but when working semirandomly I like to assign portfolios based on the domains rather than the reverse because I think it leads to more interesting combinations. Also, the models described below can lead to a single porfolio being split between many gods, leading to many gods with the same domains modeling them.)