Just wanted to weigh in with a pile of playing-card based websites that have come to my attention. Above is the most recent archive of my personal playing/tarot card collection. Here is a Flickr set depicting a charming vintage 1950s sci-fi card game called Space-O.

Here is a Russian set of playing cards with distinctively Mayan artwork.

And here is a really cool Flickr photo set of Japanese monster-themed Pachi cards.