DataMask.tech - Mask private data before taking screenshots

Snarl - Snarl is a notification system for Windows.

Image Blur - Hide your sensitive data with a click

Notify OSD - Canonicals on-screen-display notification agent, implementing the freedesktop.

Blur - Blur is a software application available for both Google Chrome and your smartphone. It's developed by Abine, an online privacy company trusted by more than twenty million people. Read more about Blur.

Notifu - Notifu, a free open source pop-up balloon utility