Pingkat's answer:
There is no many (discovered) saas based and zoro-config options for websites owner.
Pingkat's answer:
Websites / web app owners
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.
Hexowatch - Your AI sidekick to monitor any page for changes
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Trackingplan - Ensure the quality of your digital analytics.
Better Uptime - We call you when your website goes down
Phare - Run brilliant production websites