From Bulbapedia, the community-driven Pokémon encyclopedia.
Pokémon Battle e (Japanese: ポケモンバトルカードｅ Pokémon Battle Card e) is an addition to the Generation III games that utilize the e-Reader to add new content to the Pokémon RPGs of that generation.
5 sets were released in Japan, but only the first was released in the United States, Canada and Australia due to the early discontinuation of the e-Reader. As the e-Reader was not released in Europe, no Pokémon Battle e cards were released there.
There are some promotional cards which have been given out at different times in Japan, but only four of these Japanese promos have been released in English, and only in Australia. Two English-exclusive cards were also packaged with North American versions of Pokémon Ruby and Sapphire. Please see Pokémon Battle e Promotional cards for a full list.