TeamViewer - TeamViewer lets you establish a connection to any PC or server within just a few seconds.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
ConnectWise Control - ConnectWise Control is a mobile app that allows you to instantly connect with another system from anywhere with a connection to the internet. The software not only comes in a mobile app, but it has a desktop version as well for complete coverage.
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.
VNC Connect - VNC is remote access and control software which allows you to view and fully interact with one...
Prometheus - An open-source systems monitoring and alerting toolkit.