I cheat a bit and use Scaler 2's library as a starting point. It has progressions for all kinds of moods and genres, and that's usually what I'm aiming for.
It'd be cool to train text embeddings and musical chord embeddings (by analyzing song lyrics perhaps) and then build something to type in moods like "happy jaunty progression" and get a matching chord progression with a similar embedding (assuming you give it a large library of progressions). No generative AI would be needed :)