In the first episode of the anime, Ash sees a Ho-oh. Fine, right? Except for one thing. Ash was in Kanto! Ho-oh was introduced in Johto. Does this mean that Ho-oh was planned to be in generation 1?
Ho-oh was intended to be in gen 1 but was cut some point in development and actually wasn't the only Pokemon in gen 2 that was planned for gen 1. I won't list everyone here, but hereis a link to every Pokemon in gen 1 including those that were delayed to gen 2. It's also worth noting that all the Pokemon removed from gen 1 games can in a way be found by finding Missingno. As Missingno is what the games load when they can't find the data to load a Pokemon removed from the game.
