These were scanned from three different postcard sets; the first three are from one set, the next twelve are from another, and the last four are from a third set. I suspect that there's more to the first set (and possibly the third) but I don't have any idea how many are missing. Some of these illustrations are familiar, but some are things I've never seen before!
The second set of twelve was available as a mail-in prize to five lucky readers of volume 23 of Comickers magazine, but I do not know if this was the ONLY way that the set could be obtained. (I doubt it, though, it wouldn't make sense to print only five copies of a postcard set.) Just thought it was worth mentioning.
Some of these illustrations have the name Kuronuma Odile on them; this is Kojima's pen name, which translates as "Black Swamp Odile," a reference to the classic ballet Swan Lake.