some films that come to mind: MANDY (maybe my fav OST in general), DECISION TO LEAVE (understandably sparse as a soundtrack to match the movie's editing but the longer songs are so good), UNDER THE SKIN, BEYOND THE BLACK RAINBOW

as for games, i still think about the soundtrack of NIGHT IN THE WOODS a lot. the use of musical motifs is really sharp, and i like how it mixes cozy & melancholic vibes with slightly darker horror tones as the game goes on. (don't @ me because of what happened with the composer) also KENTUCKY ROUTE ZERO ofc, all the vocal songs in particular. and i am scared of mentioning it online because some people are so weird about it but i think HOMESTUCK and the accompanying works have a lot of good soundtrack work in them, too

also, obligatory furry visual novel mention: i think ARCHES has some of the best songs i've seen composed for an FVN, and they match the game's atmosphere (or, in fact, do a significant amount of work to construct it?) perfectly. really good stuff