The "Royal Road" (JP: 王道進行) is a four-chord progression that's been used in Japan for decades to write hit-making songs regardless of genre.
This eBook is a 27-page guide detailing each chord in the progression, how they function, and their most common substitutions, with score examples largely from video games and anime.
Nothing else like this exists on the internet (I had an obsession, okay), so I hope you can learn something from it.
(This PDF was originally a patron reward for my game music theory YouTube channel Ongaku Concept.)
A 27-page guide on the Japanese "Royal Road" chord progression.