I also use Google Authenticator but find the UI breaks down after a dozen accounts (I have 30+). 1 Password also supports adding TOTP but that sort of violates

I also use Google Authenticator but find the UI breaks down after a dozen accounts (I have 30+). 1 Password also supports adding TOTP but that sort of violates separating password from the second factor…so I use it only for accounts whose loss would be annoying but not devastating. I keep manual backups of the TOTP codes for all accounts, using a QR reader to decode the QR code they give out and saving the result in an encrypted file. A variant of the Google Authenticator source code is available at https://github.com/google/google-authenticator https://github.com/google/google-authenticator but is not what's on the iOS/Android app stores.