My collection within The Collection of these wonderful 1940 Superman Valentine Cards has grown by one (second row, left). Particularly fond of the bottom right one, as, apparently, it was a sign of true love back then to have Superman punch a puppy (a ways to go to save the cat in the first Donner film). Also digging the "Say Anything" move of third row left. No clue how many remain, but there are at least 13 total, and I'm sure there are more than that.