Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
GImageReader - gImageReader is a simple Gtk/Qt front-end to the Tesseract OCR Engine.
Capture2text - Capture2Text enables users to quickly OCR a portion of the screen using a keyboard shortcut.
Adobe Scan - Scan anything into a PDF using your mobile device.
ksnip - Ksnip is a Qt based cross-platform screenshot tool that provides many annotation features for your screenshots. - DamirPorobic/ksnip
Microsoft Lens - Microsoft Lens (formerly known as Office Lens) is an all-in-one application designed for Windows, Android, and Apple devices, allowing you to capture important information from signs, PDFs, whiteboards, and more to add.