Pokémon Diamond and Pearl beta
During the planning and development stages of Pokémon Diamond and Pearl, several parts were going to be a part of the games. Some of them were dropped or changed, but some of those dropped concepts of the beta version can still be found in the game's programming.
Starter Pokémon
Early during the development, the starters was meant to be changed to Psychic, Dark and Fighting types.[citation needed] This was, however, changed to the traditional Grass, Fire and Grass types, presumably to avoid confusion.
Shellos and Gastrodon
A interesting third form of Shellos and Gastrodon has been found. This form is likely a leftover from when Shellos and Gastrodon were planend to be in Ruby and Sapphire. The beta Gastrodon also has various things pointing out from it's head in the battle sprite, but is absent from both the male or female sprites. Althrough this may also be another "inofficial confirmation" of Pokémon Gold and Silver Remakes since it's PokéDex data states that it's colors and shapes differs from region to region.
Other beta-sprites
There has also been discovered other beta-sprites for Munchlax, Weavile and Cherrim. The Munchlax just seems to be a ripoof from the Munchlax-sprite in Dash. The Cherrim beta-sprite was shown in a early Japnese commercial. It is surprisingly like the final sprite, only with the left leg up instead.
Blank sign
There's a blank sign in Sunyshore City, near the Munchlax-statue.
Beta maps
A beta-map of Spear Pillar has been found. This is surprisingly like the 'normal' games Separ Pillar, but it misses the entrace to Mt. Coronet. Many also thinks that the Mystery Zone found in the Pokémon League is a beta-map.