Capture2text - Capture2Text enables users to quickly OCR a portion of the screen using a keyboard shortcut.
Scanbot - Scanbot is a mobile app that allows you to use your device's camera as a document scanner. The app is capable of scanning a large number of source materials, and it can handle QR codes as well.
TextSniper - Instantly extract any text from your Mac's screen
Scanner Pro - Scanner Pro turns your iPhone into portable scanner in your pocket.
dpScreenOCR - Program to recognize text on screen
Genius Scan - On The Go.