Way back near the beginning of DCC RPG, I wrote a book with Daniel Bishop and David Fisher called Angels, Daemons and Beings Between. The book has since been updated and has a couple of different covers. We're all working on another volume, in fact, but that's for some future post.
You'll find an adventure related to Myrddin over here ---> The Bog God's Champion
-=-=-=-=-=-=-
I was contemplating "classes" of patrons while writing the first book. Not all patrons are all-powerful entities with universe-spanning powers. Some are local petty gods, spirits and demons with limited influence and power. These patrons are eager to see their influence grow through their cultists, and thus also may have certain secret rituals and artifacts that enhance or expand their power beyond their current limited range.
Myrddin was an example of a Minor Patron -- one with a limited geographic influence, only a few invoke patron results, no granted spells, etc.
As always, let me know what you think of this one.