One of the more interesting subsets in the 1975-76 Calbee set are the artificial turf cards. The Giant's home stadium Kourakuen had just had it installed at the time and I guess it was a subject of some interest as they made at least 3 cards devoted to the subject (I have cards #406, 408 and 422 pictured above which are all artificial turf cards, there might be more that I have yet to come across.
Card 406 has a photograph of the turf being installed in the stadium (right card in the above photo). Card #408 has an illustration of the different hops that balls take off of artificial turf compared to natural turf (first bound is higher on artificial turf, but decreases in height faster with subsequent hops than on natural grass in case you are interested). Card #422 in turn (left card in the photo) shows you the structure of the installation below the artificial turf, which consists of a mix of sponge, concrete, sand, soil and something called "asucon" which I am unsure of the meaning of.
Anyway, this is kind of an odd subset, I don't think there were ever any similar cards produced when astroturf was introduced in the US about a decade earlier (though I could be mistaken about that?)
At the same time though they aren't exactly the most exciting cards in the set - except for #406 they are basically just boring diagrams. I imagine if I had been a kid in 1975 opening one of these packs hoping to see a card with an action photo of Sadaharu Oh on it I would have been massively disappointed to find one of these in it!
