Image Blur - Hide your sensitive data with a click
Snarl - Snarl is a notification system for Windows.
DataMask.tech - Mask private data before taking screenshots
Notify OSD - Canonicals on-screen-display notification agent, implementing the freedesktop.
GitGuardian - Detect secrets in source code, public and private!
Notifu - Notifu, a free open source pop-up balloon utility