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 15-20 are masterpieces of this unique genre.
Top 40 or so of this list very loosely ranked, things I've seen.
Middle section is lumped together, mostly things I haven't seen yet.
Last 25 or so are not really opera on film, but opera-related film fantasias.