OpenID - OpenID is a safe, faster and easier way to log in to web sites.
Pingdom - With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.
Portier - An email-based, passwordless authentication service that you can host yourself.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
IndieAuth - IndieAuth is a way to use your own domain name to sign in to websites.
Better Uptime - We call you when your website goes down