QuickMark - QuickMark makes everything possible.
Remote Mouse - Turn your smartphone into a wireless touchpad and keyboard now!
Barcode & QR Code Scanner - A free app which allow to read and generate barcodes for Android.
KDE Connect - Integrate Android with the KDE Desktop
ZXing - Barcode Scanner for Android
Monect - Make the best use of sensors on smart device to control PC, simulate steering wheel, game-pad...