Open Authenticator might be a bit more popular than Duo mobile. We know about 1 link to it since March 2021 and only 1 link to Duo mobile. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Call me lazy but..for phone 2FA auth I'm using Duo in personal mode (TOTP). See guide.duo.com for a start. It's convenient and fast. My Yubikey is used for PC web 2FA and, no, I don't do any financials on mobile devices. Reason I picked Duo is Google Auth on Android had dings for not being secure (some say). BEWARE of Duo, if you try to buy they only sell in packs of 30 so that first bill could be... Source: almost 3 years ago
Except Google will abandon it just like they abandoned https://code.google.com/archive/. Source: about 1 year ago
andOTP - andOTP is a two-factor authentication App for Android 4.4+
Aegis Authenticator - Aegis Authenticator is a free, secure and open source app to manage your 2-step verification tokens...
OTP Auth - The app for calculating one-time-passwords on iPhone and iPad.
Tofu Authenticator - Tofu Authenticator is an open-source easy to use two-factor authentication app that lets you secure your accounts with one-time passwords.
Caffeine for Windows - Prevent your computer from going to sleep
Authenticator Plus - Authenticator Plus generates 2-step verification codes and lets you synchronize your accounts.