Snarl - Snarl is a notification system for Windows.
Platypus - Realtime server monitoring and reporting
Growl for Windows - Growl for Windows is a Windows-compatible version of https://alternativeto.
Monitornator - Server monitoring made simple
Notify OSD - Canonicals on-screen-display notification agent, implementing the freedesktop.
NIXStats - SaaS monitoring tool for window/linux servers and websites. Think up-time robot but with more features.