Yue2 is absurdly fun to mess around with if you're a musician and basically feels like band-in-a-box on steroids. It's very easy to take old midi tracks you've written and then get Yue2 to do melodically accurate covers with modern instrumentation.

One small caveat though is that it's definitely geared towards outputting lyrics and can sometimes fight you if you're trying to make something purely instrumental.

https://mordenstar.com/other/yue2-tests