Hyperping - Cheap uptime and performance monitoring with detailed reporting and flexible alerting

UptimeRobot - Free Website Uptime Monitoring

Simple Ops - Simplify website performance and uptime monitoring with alerting, ssl check, chrome ux metrics, multi locations

UptimeRobot App - Web, SSL, ports & Cron-jobs monitoring

Pulsetic - Pulsetic makes monitoring your SaaS products simple and easy with Status badges to show the status of the site without changing pages and you will also be alerted when your site goes down.

Secure My Website - A pain-free service to add SSL to your site, for non-geeks