Myutsu(Mewtwo) no Gyakushuu/MewtwoVSMew Original movie trailer.
First some explanations: The original pokemon Anime serie was programmed to finish after an half-year season with Ash becoming the champion of Indigo League,following the original plot of the game.
The first movie,MewtwoNoGyakushuu(the counterattack of Mewtwo)/Mewtwo VS Mew for short,was originally created to be a sort of "final" for the serie,and as it can be seen here it was different from the actual canon-version.
Then in this trailer is shown the original ending of the serie,with and adult Misty and a child that is probably Ash/Misty's daughter.Ash is not present,probably still following his destiny as a champion of the league in distand lands....leaving Misty and their daughter alone looking at the sky.
But the serie wasn't over in this manner, so it must be seen as a "non-canon original ending"
What pokemon Anime's ending will be now....only time....a lot of time will tell.