GImageReader - gImageReader is a simple Gtk/Qt front-end to the Tesseract OCR Engine.
ShareX - ShareX is a free and open source program that lets you capture or record any area of your screen...
Adobe Scan - Scan anything into a PDF using your mobile device.
Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
Adobe Acrobat DC - Make your job easier with Adobe Acrobat DC, the trusted PDF creator. Use Acrobat to convert, edit and sign PDF files at your desk or on the go.
LightShot - The fastest way to take a customizable screenshot.