Opsmatic - Opsmatic offers complete system visibility and configuration monitoring for fast-moving technical teams.
The Dude - MikroTik is a Latvian company which was founded in 1996 to develop routers and wireless ISP systems. MikroTik now provides hardware and software for Internet connectivity in most of the countries around the world.
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.
Pandora FMS - Pandora FMS: Opensource monitoring software
Guacamole - Access your computers from anywhere. Because the Guacamole client is an HTML5 web application, use of your computers is not tied to any one device or location. As long as you have access to a web browser, you have access to your machines.
cStatus - Monitor and scan a network.