Tesseract - Tesseract is an optical character recognition engine for various operating systems
Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
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
Capture2text - Capture2Text enables users to quickly OCR a portion of the screen using a keyboard shortcut.
ABBYY FineReader - ABBYY's latest PDF editor software, FineReader 16 you can easily convert files like PDF to Excel, PDF to Word, edit, share, collaborate & more with this PDF editor!
ksnip - Ksnip is a Qt based cross-platform screenshot tool that provides many annotation features for your screenshots. - DamirPorobic/ksnip