Since you can now login to certain OSX/iOS apps using your Apple ID credentials rather than with an application-specific account, is there a way to list all of the apps you have granted access to and edit their permissions (something like what Google does when you authenticate using your Google credentials)?
In iOS, Go to Settings > Your name > iCloud > List of apps.
You can turn on / off any of the apps using your Apple ID
Could not find anything else in iCloud that comes close. However it is a great feature request! You can give feedback about this to Apple.
Answering my own question: this is currently not possible, there is no way to see what apps / services you have authenticated with using your Apple ID.