PaperCards.com has Christmas cards divided up into 43 different categories (Pop Up, Patriotic, Disney, Nature, Spanish-language, Animal) and you can buy single cards or batches. They have cards with African-American angels, Madonnas and Santa. Oddly, they have only four Hanukkah cards available.
If you're looking for one of a kind humorous greeting cards for the season, Snafu Designs can hook you up. I'm partial to their "Fleas Navidad" card. Tiny Prints cards are on sale all this week (Why have Cyber Monday when you can have Cyberweek?) Check them out for something different in personalized cards.