Snarl - Snarl is a notification system for Windows.
Notifo - Notifo is a mobile notifications platform empowering developers to build their own services with a...
Notifu - Notifu, a free open source pop-up balloon utility
Growl for Windows - Growl for Windows is a Windows-compatible version of https://alternativeto.
Notify OSD - Canonicals on-screen-display notification agent, implementing the freedesktop.
notify.uno - Get notified when your commands are done.