From Bulbapedia, the community-driven Pokémon encyclopedia.
This article lists all cards featured in the Pokémon Trading Card Game compatible with the e-Reader peripheral and their associated card ID.
The card IDs are ordered in a similar manner to the Japanese ordering of cards during the e-Card Era: by type, National Pokédex number, and ascending rarity. This ordering remains the same for the early English EX Series expansions that continued to support the e-Reader, despite the difference between the Japanese and English expansion ordering systems at the time.
The card IDs increment alphabetically based on Japanese releases, thus the English e-Card Series expansions encompass two sets of IDs due to their consolidation. There is a clash of language-specific card IDs at 'M' due to the handful of cards included in the English EX Team Magma vs Team Aqua expansion, the Japanese McDonald's Pokémon-e Minimum Pack, and select cards used for the Sample Set. It is unknown as to why the English releases bypassed 'J' and 'L' during the EX Series.
It's not known what IDs the original 2001 Japanese Press Conference Sample Set cards had, but thanks to pictures from the 2001 Japanese Space World event it is known that the Sample Set cards from that had IDs prefixed with 'R' - possibly to denote these as examples as the word 'example' is 例 Rei in Japanese.
List of card IDs