Google Authenticator has a feature to allow export of all saved codes into one QR code for re-import into Google Authenticator running on another device. I printed a copy of my export QR code for use in case my device is lost or stolen.
Thanks! I hadn't seen that feature. Just checked it out. It shows multiple QR codes (in my case 2 QR codes which contain 11 TOTPs total) that you can scan from another device running Google Authenticator to transfer to codes. I guess I can screenshot those QR goes to back up (scary)