In April 2020, a leaked copy of the source code of Pokémon Gold and Silver was released on the internet. The source code was found to contain a sea of pre-release material detailing the development of Generation II.
In these files is a collection of sprites found in an internal backup dated May 6, 1998. These sprites represent a later version of the game than the one seen in the Spaceworld '97 demo, and include many cut Pokémon that have not been seen elsewhere to date. Any additional data regarding these scrapped Pokémon (names, move data, stats, evolutionary data, etc.) is not known to exist. The first 151 Pokémon match the Pokédex order, while the others appear to be strewn about haphazardly, seemingly without much care. These sprites shown depict the older designs for Raikou, Entei, Suicune, and Bayleef.