Growl for Windows - Growl for Windows is a Windows-compatible version of https://alternativeto.
Communifire - Enterprise Social Collaboration Software
Notify OSD - Canonicals on-screen-display notification agent, implementing the freedesktop.
Bonzai Intranet - Bonzai is an intranet platform with flexible pre-built features for SharePoint and Office 365.
Notifu - Notifu, a free open source pop-up balloon utility
hub - The Hub is a versatile intranet portal and collaboration solution that boosts employee engagement and productivity in a digital workplace.