NIXStats - SaaS monitoring tool for window/linux servers and websites. Think up-time robot but with more features.

Nagios - Complete monitoring and alerting for servers, switches, applications, and services

Server Monitoring - A server monitor is a tool that monitors your server and website on close intervals and reports to you if it's inaccessible.

Gitwin - Enable your Windows system as a powerful and secure Git repository. Supports ssh, http(s) transports. Gitweb with highlighter and gravatar support available.

Nubity - Nubity provides SaaS-based, centralised public and private cloud manager platform to manage and monitor servers.

LANState - LANState - Network Mapper and Device Monitor