One copy each was given to those three music artists in 2021. Here some info about it on Pokebeach.
And here a picture of the physical Balvin J card:
If you haven’t seen it yet, I’ve created an article about it: Protostoise - putting the puzzle pieces together.
Speaking of articles, the Teach/Tryout Set cards aren’t too well-known either, and the ones from 2011 even have unique artwork not used on other TCG cards:
Japanese Teach/Tryout Sets.
Greetz,
Quuador