These are fully realized opera films (and short films) as opposed to filmed versions of stage performances. A unique genre that has a few outstanding entries. Syberberg's "Parsifal," Bergman's "Magic Flute," Strauss/Huillet's "Moses and Aaron," and Powell's "Tales of Hoffmann" are all acknowledged film masterpieces. But there are a couple of dozen others that are brilliant and fascinating films in their own regard.
Top 35 or so of this list are loosely ranked.
Last 15 or so are not really opera on film, but opera-related film fantasias.