Tamashii Hiroka from Youtube has this cool series where she analyzes the alpha and beta versions of Pokemon games and how much has changed. Like, a whole crapload of things changed between generation 2's playable demo and the final version, starters included!



There'\s also this unused Pokemon that probably changed into either Tyrogue or Hitmontop



Then there's gen 3, where it looks like Latias and Blaziken were originally conceived as one Pokemon



Also, Torchic used to have a slightly different design