I do not include shorts, documentaries, live musicals or musicals on stage in this list, as they are not considered "feature film musicals". I do have quite a bit of TV musicals on here, though.
This list has been and always will be constantly updated. Many are out of order, as it's extremely difficult to go back and shuffle with such a huge list on here.
Excluding these because they are not in Letterboxd's library:
The Song of Love (1929)
Great Day (1930)
The March of Time (1930)
Idols of the Radio (1934)
Susie's Romance (1934)
Ebony Parade (1947)
Rhythm in a Riff (1947)
Bud Townsend's Alice in Wonderland (1976)