NIXStats - SaaS monitoring tool for window/linux servers and websites. Think up-time robot but with more features.
EasyCron - Get frustrated with Cron on your server? Hosting limits your Cron use?
Server Monitoring - A server monitor is a tool that monitors your server and website on close intervals and reports to you if it's inaccessible.
crontab guru - The quick and simple editor for cron schedule expressions by Cronitor
mackerel.io - mackerel.io is a server and application performance monitoring platform.
Cronitor - Monitor cron jobs, micro-services, daemons and almost anything else, no setup required. Easier cron troubleshooting and no more silent failures.