Bitwarden Authenticator is a standalone app that is available for everyone, even non-Bitwarden customers.
In its current release, Bitwarden Authenticator generates time-based one-time passwords (TOTP) for users who want to add an extra layer of 2FA security to their logins.
There is a comprehensive roadmap planned with additional functionality.
Available for iOS and Android
Privacy friendly Ente has an E2EE cloud backed up authenticator app called Auth. In case you didn’t want to host your own, or need multi-device sync.
Or you can just self host Bitwarden and use the built in 2FA that can be attached to any login