If necrozma is indeed in the new Pokemon movie
Games
September 12, 1998 yellow
December 14, 2000 NA July 25th 2001 crystal
September 16, 2004 emerald
September 13, 2008 platinum
June 23, 2012 BW2
November 18, 2016 sun and moon
Movies
July 18, 1998 Pokemon the first movie
July 7, 2001 pokemon 4ever
July 17, 2004 Pokemon destiny deyxos
July 19, 2008 Pokemon girtina and sky warrior
July 14, 2012 kyrmun keldo film
July 16, 2016 volcanism movie with zygard and magerena
The 3rd version of the game had the legendary in the movie the same year.
In zygarde case it was quest and in sun and moon.
So we're either gonna get a necrozma 3rd version or a game with necrozma in it