Nagios - Complete monitoring and alerting for servers, switches, applications, and services
Splunk - Splunk's operational intelligence platform helps unearth intelligent insights from machine data.
Gitwin - Enable your Windows system as a powerful and secure Git repository. Supports ssh, http(s) transports. Gitweb with highlighter and gravatar support available.
NewRelic - New Relic is a Software Analytics company that makes sense of billions of metrics across millions of apps. We help the people who build modern software understand the stories their data is trying to tell them.
NIXStats - SaaS monitoring tool for window/linux servers and websites. Think up-time robot but with more features.
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.