This is a work in progress. Please ignore for the time being. Or offer suggestions, that works too.
No biopics UNLESS the artist plays themselves and no established musicals (Dream Girls, for example), but movie musicals that were stage musicals FIRST (Once) count.
Extended music video movies are a tough one. I think they count as long as the artist appears as a lead (Moonwalker, Graffiti Bridge), but not when the band is largely off-screen or just performing (The Wall?).
Elvis movies were hard, because he kinda plays himself in a lot of them. Hopefully I narrowed it down to a reasonable few.