Raagas are like scales (which is a massive reduction though) because they are a bit more complicated. Each raaga has time, emotion attached to it as well - there are raagas you can use in a time of a day (in the morning, but not evening for a evening song etc). But yes, scales are the closest it comes to.

There are 72 major raagas - called mela kartha raagas - those are the root raagas, and there are combinations and permutations done that generates the janya raagas - which is children raagas (there are thousands of those - and different artists can create variations on these).

Most films in Hollywood have narrative beats - its 7-8 beats. Each tv show for eg, has 5-6 beats. Most micro drama episode has 2-4 beats. Its quite structure that way.

If you take a structure like Save the cat, or Heroes' journey, the order of the beats are also quite well laid out - just that those two structures dont cover the span of stories, and rest is all quite undocumented.

Im trying to work backwards - and quite aware that i am probably identifying derivatives than the root, but even the derivatives can be quite useful to guide others from generating engaging content.

I am not aware of Aarne Thompson's work. I'm looking it up right now...