Record Corner (FireRed/LeafGreen)
Unused map locations | Early English promotional Pokémon names | Eternal Flower Floette | Bird type | Unused music | Unused encounter system (Yellow) | Unused Bulbasaur slot machine symbol | Unused Shadow Pokémon | Cacophony | Unused Japanese list strings (Generation I) | Unused items | Unused Pokémon data | Unused and redundant Egg moves
See also:
S.S. Anne Ship Truck
In Pokémon FireRed and LeafGreen data exists for a map resembling the records room in Pokémon Ruby, Pokémon Sapphire and Pokémon Emerald regardless of the fact that the room could no longer be accessed in these games through the use of the Pokémon Center and the fact that the Mixing Records feature was removed from the game.
It exists for unknown reasons, however it may exist due to the fact that Nintendo would often use their older games as a template for their newer games. In the case of Pokémon FireRed and LeafGreen, maps such as Route 201 would eventually have to be removed from the game, however since the Records Room still exists within the game this may suggest that Nintendo were to presume that as was the actual case with rooms such as the Colosseum the Mixing Records feature would eventually make it into the final game.
External links
[1] - A Youtube video of a player entering the Records Room in Pokémon FireRed and LeafGreen, through the use of a game-altering device.