UptimeRobot - Free Website Uptime Monitoring
Freshservice - Freshservice: the one-stop cloud solution for all your IT management needs.
StatusPage.io - StatusPage.io is the best way for web infrastructure, developer API, and SaaS companies to get set up with their very own status page in minutes. Integrate public metrics and allow your customers to subscribe to be updated automatically.
Freshdesk - Freshdesk is a cloud-based customer support software that lets you support customers through traditional channels like phone and email, social channels like Facebook and Twitter, and your own branded community
Freshworks - Delight your customers, from wherever you are
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.