Looks like there were a lot more people interested in Pokemon Battle e cards than I thought! With that said… Time to show you some of the rarest pokemon battle e cards to exist (Besides Demo Card P-008). The Ruby/Sapphire battle e set had club Nintendo exclusive cards. More information here: Pokémon Battle e Promotional cards - Bulbapedia, the community-driven Pokémon encyclopedia
These are incredibly difficult to find. Enjoy!
Ruby/Sapphire: Total of 8 trainer cards. I am unfortunately missing the original manual for these.
I had been holding off on battle e cards to catch up on Eeveeutions. But I guess now I have a lot more motivation to pick up what I’m missing. Which is a lot, but I’ve always loved these cards as a kid. Even though I didn’t get an e reader until last year.