DroidPad is described as 'lets you use your Android powered phone as a Joystick for your PC'. There are more than 10 alternatives to DroidPad for a variety of platforms, including Android, Windows, Android Tablet, iPhone and Linux. The best alternative is Monect, which is free. Other great apps like DroidPad are LEA Extended Input (Freemium), Max Remote (Free), Wifipad (Free) and aGamepad (Free, Open Source).
BT Controller turns your Android device into a controller for any emulator that supports custom buttons. FEATURES • Play console games anywhere • Control emulators on your TV, Tablet, or Phone • Supports up to 4 players • Use Bluetooth or Wifi to connect your devices
Kutimo is a wireless gamepad for Windows with a focus on customization. Use the controller editor to add any number of buttons and directional pads anywhere you like on your device screen. Bind up to 10 keys to a single button press using the Kutimo client on your PC.