WebGazer is an uptime monitoring platform that checks if your website is up as it should be and notifies you if anything goes wrong
UptimeRobot - Free Website Uptime Monitoring
Checkout X - Checkout X is an all-in-one, checkout platform optimized to maximize conversion rates and revenue on WooCommerce stores.
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.
Instant - Your life on a dashboard, automatically track your activities!
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
WPFunnels - We are building a unique visual Sales Funnel builder in WordPress and are looking for Beta Testers.