Which japanese promos are you talking about? The unnumbered promos from about 1996 to 2005? Can you give an example? I have nearly all the japanese promos from 96-2001 excluding the trophy cards. I know many are magazine promos like natta wake and coro coro.
@carrot I think you’re talking about the T Promotional Cards that came in the Trainers Magazines:
If so, I believe the artworks are unique to the set (experts correct me if I’m wrong).
Scott did a video on them:
The Larvitar evolution line was also printed in POP Series 1. The rest are unique as far as I know.