Hyperping - Cheap uptime and performance monitoring with detailed reporting and flexible alerting
UptimeRobot App - Web, SSL, ports & Cron-jobs monitoring
Simple Ops - Simplify website performance and uptime monitoring with alerting, ssl check, chrome ux metrics, multi locations
Cronitor - Monitor cron jobs, micro-services, daemons and almost anything else, no setup required. Easier cron troubleshooting and no more silent failures.
Monitor Buddy - Simple & cheap uptime monitoring service
Curler - Dead Simple Free Uptime Monitoring