I plan on including three new patrons in GCC--Orpheus, Echidna, and Prometheus.
In GCC, Prometheus is something of a messianic figure. He's the creator and patron of humanity, suffering now for his crime of stealing fire for humanity. Theoretically, the PCs will eventually get a chance to help Hercules free him from his bonds.
As a patron, Prometheus' gifts are based around fire, foresight, trickery, and creation. He only grants patronage to those who fight for the common good of mankind.
Below is the Promethean Invoke Patron table I've been using in my playtests. I'm sure it will continue to be tweaked. Enjoy!
(Also, Brendan Lasalle is including Prometheus as a patron in X-Crawl. I haven't seen it yet, but I'm eager to see how similar/different it is from mine.)