AutoMusic is almost definitely the world's most fully-featured toolset for procedurally generating music in real-time in Unity.
Input is individual sounds , that the tool provides a variety of method for arranging into rhythms & tunes, and creating evolving compositions of those sounds featuring any number of instruments.
It features multiple instruments, devices for modifying the output of those instruments, instruments that can inherit & adjust the content of other instruments, custom fx for adding sound design to individual notes, and many other features for creating music.
All of this happens in real-time & will continue until you tell it to stop.
Much of the processing is tucked away on the audio thread out of harms way of the main thread.
As well as the audio side, I have components for generating visuals based on the output of those instruments.
My contribution on this project is everything.
Made in Unity / written in C#
Some fx flipbooks created using Embergen
https://www.youtube.com/@SchnauzerCorp
https://www.schnauzercorp.net/