The Unknown Gods was a Judges Guild supplement, detailing many minor but strange deities. In 2010, James Maliszewski put out an open call on the Grognardia blog for submissions for a new version, to be called Petty Gods (inspired by a post by Blair Fitzpatrick on the Planet Agol blog), and began the initial work compiling the entries and art. While the project fell through, the mostly-finished 150-page version (edited and laid out by Peter Gifford in 2012) was released by Greg Gorgonmilk in 2013 as the "Original" Petty Gods.

The Revised & Expanded Edition is a continuation of that work, but with more than 300 godlings, over 100 minions, and dozens of cults, spells, and magic items, has swelled to almost 400 pages. Richard J. LeBlanc, Jr. compiled the work of the 150 plus contributors