the entire jazz tradition is based off of improvising new melodies over the same songs (jazz standards)

probably not exactly what you mean but figured it was worth a mention

You got me thinking about this. I thought it would be more common in the classical era with key names in the title, like Sonata in Eb or whatever. Having chatted with an LLM about it, that case doesn’t seem that common once you start considering Opus and Symphony numbers. I think you have to be a bit tricky to pretend that this happens often during that era (or maybe the opus numbers came after? I don’t know).

But in “modern” pop it looks like it happens a lot (from ChatGPT):

“Hello” • Adele — F minor • Lionel Richie — F minor

“Crazy” • Gnarls Barkley — G minor • Aerosmith — G minor

Which case / level of pedantism were you thinking of?