I have come across this music trainer website and I really enjoy playing all the games and learning to recognize music. I do prefer playing some games and learning something out of it.
You need to create an account and then you can play every game up to 3 levels after that subscription is needed. It is very similar to Lumosity (brain trainer…) where you play games to improve memory and other mental stuff.
i’ve found an app for training your ears towards an absolute hearing: https://play.google.com/store/apps/details?id=ear.trainer
this one i’ve used but you can find many more of such apps… just try searching for “absolute” and “ear” or “hearing” or something like that…
furthermore, this app is for android… idk, if there are some apps for iOS but i’m pretty sure, there are some