GImageReader - gImageReader is a simple Gtk/Qt front-end to the Tesseract OCR Engine.
Yandex.Images - search for images on the internet, search by image
Adobe Scan - Scan anything into a PDF using your mobile device.
TinEye - Reverse Image Search to help find an image's source, duplicates or altered versions.
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.
SauceNAO - SauceNAO is a reverse image search engine.