Haystack Search - Haystack helps you make the most of your time, by searching all your files and documents in the cloud in one place. It's been built for privacy from the ground up, so your data isn't stored on a server, just your computer.
Google Lens - Discover information about something by taking a photo
MailJack+ - Send PDFs as postal mail
GImageReader - gImageReader is a simple Gtk/Qt front-end to the Tesseract OCR Engine.
Paperkit - Create and download custom graph, lined, or dot grid paper
OpenScan - FOSS Document Scanner