a few years ago-(like 6 or7) a 'seasons' post card swap- meaning 4 swaps- 3 months apart- depicting the season of that quarter--
i have a great assortment of fabric postcards from all over the country (and Canada)
they all came to me through the mail- with postmarks- they are great!
there is a (trading card) group- who make them trading card size (like the art cards) and send those and trade them too