Tesseract - Tesseract is an optical character recognition engine for various operating systems
TextGrabber - Office & Productivity
GOCR - GOCR homepage. GOCR is an OCR (Optical Character Recognition) program, developed under the GNU Public License.
LetterScan - Never type a text out again.
ABBYY - ABBYY's leading AI and machine learning technology solutions range from process analysis, data capture, pdf editor, text and content recognition (OCR) and extraction, combining process and content insights to deliver digital intelligence.
Onlineocr.net - Free Online OCR service allows you to convert PDF document to MS Word file, scanned images to editable text formats and extract text from JPEG/TIFF/BMP files