Zendesk - Zendesk is a beautiful, lightweight help-desk solution.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Freshservice - Freshservice: the one-stop cloud solution for all your IT management needs.
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
ServiceNow - ServiceNow automates and manages global enterprise service relationships. Create a single system of record for enterprise services, automate manual tasks, consolidate legacy ITIL systems.
Prometheus - An open-source systems monitoring and alerting toolkit.