Prosper, Tome-Bound signposts two very obvious themes: exiling cards and utilizing Treasures
For example, Sword and Shield Base Set cards are different than any of the Scarlet and Violet expansions
Another interesting little note, you see that barcode number in the bottom right of the label
The cute play is to steal counters from opposing creatures, which people dont know you can do until you say youre doing it
Repentance takes this up to eleven by having a Secret Alternate character for every character in the roster, including the Secret Characters listed above
I've heard whispers of them popping up in various locations beyond grocery stores like my Jewel Osco think malls, entertainment centers, and even other retail chains like HEB in some regions