This is the app that King Crimson used live last I saw them in concert. I've had it for years and love it. It will however no longer be supported and will eventually fail on some iOS update, but you can always install it on an old device that no longer can be updated. It works on quite old iPads. I've tested ;)
https://synthanatomy.com/2024/06/omenie-discontinues-its-ios-app-portfolio-mellotrons-and-free-download-for-a-limited-time.html
Just got the Omenie Steelytron Pro app on iOS - free and working. 90 mellotron voices!
This is brilliant - thanks Geir!
Magic! got the mellotron too or should I say two as there are two versions.