I haven't found a list on Letterboxd like this yet, so here one is: a list of movies that are actually compilations of different shorts or scenes or segments from various recognized directors. Sometimes they are all part of the same story, sometimes they have the same theme, etc. Three or more directors have to contribute to the film to be considered an anthology IMO, so that's my criteria.
Extremely uncomprehensive at the moment; please help me out! I have seen almost none of this type of movie before, so please help me out here!! (Though due to the sheer volume of obvious absolute garbage, I won't be adding any collaborative horror anthologies unless they have notable directors or enough popularity. View this list of horror anthologies though if you are interested: letterboxd.com/thenomad/list/ultimate-anthology-horror-list-1/)
(Side Note: The Mission: Impossible franchise is essentially a long-form version of an anthology movie set around the theme of Tom Cruise doing stunts. Wow /deep)