Classical music in the movies.
Someone on Hacker News asked where to find "free to remix" music.
Well, pretty much all classical music scores are off-copyright (getting more modern every year) and of course, there are creative commons performances, many by college orchestras or off old LP's at the internet archive, some at imslp.org (though they seem to love to say "non-PD US" a damn lot.
I did a quick search for some faves, and here are some with "top ten or so" lists
https://houstonsymphony.org/10-times-classical-music-starred-in-movies/
https://www.lso.co.uk/seven-times-classical-music-was-used-in-film/
https://www.thomann.de/blog/en/10-most-used-classical-songs-in-movies/
https://www.classical-music.com/features/tv-and-film-music/six-best-classical-pieces-film
https://www.cmuse.org/classical-music-moments-in-movies/
Last, but not least:
https://coloradosymphony.org/best-classical-music-in-movies/
No YouTube embeds, but you're probably already seen them in the above.
Note that the converse is not true. Music written contemporaneously with movies is likely still under copyright.
Too bad, John Williams. Love my Mozart and Rachmaninoff (and lots of others).
What movie have I re-watched just for the music? The Pianist.
Yikes, they cut a beautiful section of the Ballade in G minor
Most fun classical music in a movie? A Night at the Opera, mostly IlTrovatore, a little I Pagliacci, and "Take me out to the ballgame" thrown in (as a curve ball).
It all started with Fantasia, of course. Thanks, Mom and Dad!
Goofiest? Chico playing a 5 - 2 with the right hand. (pinkie-index)
Or the "magical" index finger (2)