Raivo Authenticator is described as 'Native open-source app for iOS and macOS generates time-based one-time passwords, supports secure iCloud sync, FaceID unlock, QR scanning, and encrypted backup' and is a Authenticator in the security & privacy category. There are more than 25 alternatives to Raivo Authenticator for a variety of platforms, including iPhone, Android, iPad, Android Tablet and Linux apps. The best Raivo Authenticator alternative is Aegis Authenticator, which is both free and Open Source. Other great apps like Raivo Authenticator are Ente Auth, 2FA Authenticator (2FAS), Authy and Google Authenticator.
Aegis is Android only whilst Raivo OTP is iOS only