Tab2QR lets you quickly send a webpage from your desktop over to your mobile device using a QR code.
Scanbot lets you create high-quality digital copies of your physical documents on your devices.
Lensinator lets you find objects and scan for various codes on your Android device.
If you use QR codes on multiple devices, QR Sync will be a useful app for you as it helps synchronize codes across your devices.
QR Code Reader is a free QR code scanner app for Android and iOS devices.
QR Code Generator is a free app that allows you to generate various kinds of QR codes on your Android device.