Sara Preciado made a lovely video that places scenes from La La Land right next to other scenes from musicals and movies that La La Land was obviously referencing. It’s fun to watch (and I say that as a person who doesn’t really get into musicals) because it reminds you of all the peppiness and cheeriness that musical numbers have, without drowning in it.
I agree with a lot of those, but some are kind of a stretch. The first one that didn’t really mesh well to me was the “West Side Story” reference where she’s got a curtain wrapped around her. You could say it was a reference to “Frozen” too, since the character wrapped a curtain around her in that musical too. A lot of them were spot on though!