TextSniper - Instantly extract any text from your Mac's screen
Google Lens - Discover information about something by taking a photo
LensOCR - Scan anything from your Mac's screen.
GImageReader - gImageReader is a simple Gtk/Qt front-end to the Tesseract OCR Engine.
OwlOCR - OwlOCR offers simple optical character recognition of text in PDF files, images or on-screen and converts that to plain text.
OpenScan - FOSS Document Scanner