2 x Raspberry Pi, Arduino Joystick Module shield Button Game Sensor | eBay
Arduino Expansion Shield for Raspberry Pi model B - DFRobot
Amazon.com: Raspberry Pi AD/DA Expansion Shield Board Onboard ADS1256 DAC8552 Sensor Supports Adding High-Precision AD/DA Functions to Raspberry Pi : Electronics
Prototyping Shield for Raspberry Pi 3/ Pi 2/ Model B+
Raspberry Pi vs Arduino: Which Board is Best? | Tom's Hardware
Dfrobot Arduino To Raspberry Pi Mcu Shield Dfr0327,designed To Combine Your Raspberry Pi Computer Board With An Arduino Board - Demo Board Accessories - AliExpress
Connect the Raspberry Pi Zero to an Arduino with This Compatible Shield - Hackster.io