Google Authenticator - Google Authenticator is a multifactor app for mobile devices.
Domainz.io - Premium domains, for not so premium prices
Microsoft Authenticator - One app to quickly and securely verify your identity online, for all of your accounts.
Amazon Route 53 - Amazon Route 53 is a highly available and scalable DNS web service.
LastPass Authenticator - LastPass is an online password manager and form filler that makes web browsing easier and more secure.
Undeveloped - Domains you never thought were available