Seeing AI is a free App from Microsoft that is currently supported on iOS. This one tool does the job of many other Apps and includes bar code scanning; screen reading; facial, colour, currency and scene recognition. This product is still under development but has potential.
With facial recognition, you can name and store the faces of students in your class, colleagues at work or people in your community so you can recognise them when they approach.
While the optical character recognition may not yet be as accurate as other tools, the ability to carry this functionality in your pocket makes it very convenient. The currency identifier and colour identifiers were reasonably accurate and the barcode reader was useful in differentiating spice jars.