I think it's kind of a misnomer to say they were US cart only releases, when in fact they were never released at all in the US. All that seems clear right now is the boxes probably existed at some point, at least the prototype plates for printing them, and then oops, everything was recalled back to Japan (or Hong Kong). We will never know which were released until we see carts with ESRB on them turn up. Probably a search in the ESRB database will turn up all these titles.