I’m using Raivo. It’s open source, supports iCloud sync (useful if you have multiple devices) and allows you to export and import the keys which is handy if you need to change your device and you don’t use iCloud synchronization.
You can also set custom icons for the tokens to easily identity different services.
I switched from mattrubin/Authenticator which worked fine too but the development slowed down. Not that simple OTP would require constant development. I just wanted to make sure that the app would work even if Apple releases new major iOS version.
Raivo has worked without any issues and I can highly recommend it 👍
Perfero caffe' Sumatra Lintong Bio beans, grinding manually and brewing with Hario V60. A splash of Finnish barista oat milk for the finishing touch.