Unofficial hardware

1 Displays

• Adafruit PiTFT Touchscreen 2.8" (Clonic versions too!)
• OzzMaker PiScreen 2
• WaveShare TouchScreens with GPIO connection for touch-device
• Official Raspberry Pi Foundation 7" TouchScreen
• Generic HDMI Touchscreens with USB mouse-like-touch-device

2 Audio interfaces

2.1 Tested good

• HifiBerry https://www.hifiberry.com/products/
  • HifiBerry DAC+ => hifiberry-dacplus
  • Hifiberry DAC+ Pro => hifiberry-dacplus
  • HifiBerry DAC+ Lite => hifiberry-dac
  • HifiBerry Amp => hifiberry-amp
  • HifiBerry Digi => hifiberry-digi
• IQAudio http://iqaudio.co.uk/3-audio
  • IQAudio DAC+ => iqaudio-dacplus
  • IQAudio DAC => iqaudio-dac
• AudioInjector http://www.audioinjector.net/
  • AudioInjector Hat => audioinjector-wm8731-audio

2.2 Tested bad

• Built-in Raspberry 1/8" audio jack. The onboard RBPi soundcard is not suitable at all. It's PWM based (no DAC!) and only 10 bits of resolution. Also, it has a huge latency. Forget getting a decent result with it. You have to use a decent soundcard (with a DAC!) for RBPi.
• USB audio interfaces (latency problems)

2.3 Untested

• PiSound https://blokas.io/
• Sparkfun JustBoom HAT
• Built-in Raspberry HDMI audio