Behind the Name - My go to site for random names.
Vaults of Pandius - An official fan site for Mystara.
World of Mystara Wiki --> Gods - I couldn't find a list of Mystaran gods in any of the PDFs I own. Not sure how accurate this one is but at least it's something.
Non-Player Cards - Metal Weave Games produced a boxed set with eight 50-card decks for randomly generating NPC characteristics. Now only available in book form plus PDF.