Simple Ops - Simplify website performance and uptime monitoring with alerting, ssl check, chrome ux metrics, multi locations
Hyperping - Cheap uptime and performance monitoring with detailed reporting and flexible alerting
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
UptimeRobot App - Web, SSL, ports & Cron-jobs monitoring
Odown - Simple and reliable uptime monitoring service + public status pages