Just realized this site I used a while back might be something folks here would enjoy ..
Smarter Playlists
It's a web site that you link your Spotify account to and you can generate playlists with it
I use Apple Music now, and there's an app called Miximum that does the same thing. I like it more because the Spotify one doesn't add songs you've burned from CD to its playlists (it needs the API info, or whatever they call it).