GImageReader - gImageReader is a simple Gtk/Qt front-end to the Tesseract OCR Engine.
TagSpaces - TagSpaces is an open source platform for personal data management. With TagSpaces you can manage and organize the files on your laptop, tablet or smart phone.
Adobe Scan - Scan anything into a PDF using your mobile device.
TagFlow - TagFlow is an intelligent files manager that use tags for organize your documents.
Tesseract - Tesseract is an optical character recognition engine for various operating systems
Tabbles - Tabbles use tags to organize and find files along with your colleagues.