I did however pick up one interesting thing recently. "Stop Motion Assembly Model" baseball cards of Shigeru Kobayashi and Masayuki Kakefu.
I'd never heard of these before and didn't even know that I should be looking for them. They were in a big "junk" lot of random 70s cards I bought on Yahoo Auctions a few days ago. I didn't even notice what they were in the lot pictures and it only became apparent when I had them in my hands.These are basically die cut wood figures that are meant to resemble the players on the card as you can see when you flip them over.
These are still sealed in their original packaging so I haven't opened them up, but you can see from the image on Kakefu's what they are supposed to look like when assembled. Not impressive by today's standards when we are used to very life-like plastic figures, but not bad for the 1970s.
These were produced by a company called Mitsubishi Pencil which confusingly has the same name (Mitsubishi) and logo as the more famous Mitsubishi industrial conglomerate but isn't actually a member of it.
Given the appearance of Kobayashi as a Giant and Kakefu as a Tiger, these would have been produced sometime between 1974 and 1978. They had a retail price of 250 Yen (on the upper left corner of the package).
I'm not sure what, if anything is on the back of the cards (which are roughly postcard sized) since I haven't taken them out of the package.
These seem to be pretty rare. Engel doesn't mention them at all, I've never seen them on Yahoo Auctions before and my Google search for them turned up a grand total of one relevant result. That result was kind of intriguing, it was an image (on pinterest) of this ad here for them:
This is not actually an ad from Mitsubishi Pencil, the producer of them, but rather by Morinaga Caramel which produces a well known caramel candy (pictured in the bottom right of the ad) which is still sold in most convenience stores today. I can't quite read all the small text in the image, but it seems like these were given out as presents to those who bought a certain number of Morinaga Caramels and sent in the proofs of purchases. Given that Morinaga Caramels only cost 50 Yen each and the retail price of these figures was 250 Yen, I'm guessing these didn't sell well initially and they ended up giving the leftover stock to Morinaga to dispose of through this promotion, though I'm not sure.