I2C Shield for Arduino Nano - RobotShop

JSumo Wing Arduino Robot Controller (w/ Arduino Nano) - RobotShop

RS485 CAN Shield for Arduino - RobotShop

Terminal Shield for Arduino - RobotShop

Compatible with BLE Link (BT4.0)/Bluetooth Bee (BT2.1). Embedded DS1307 RTC module to keep time of the Pi. 3 pin headers sensor port for Arduino pins and B+ GPIO. The Arduino Expansion Shield for Raspberry Pi B+/2/3 makes it possible to extend Arduino shield features for your Pi. When building a mobile robot, the Raspberry Pi is used to extend its vision and get a nice tiny monitor.

DFRobot DFR0327 Arduino Expansion Shield for Raspberry Pi B+/2/3

It is both a RS232 shield and also a RS485 Shield for Arduino. It can easily convert UART to RS232 or RS485 interface. The shield integrates DB9 connectors (female) that provide connection to various devices with RS232 interface and also provide a RS485 screw terminal interface. It provides the prototyping areas to make full use of extra space on it, which is highly convenient for prototyping. This shield provides 2 mode setting switch. UART/Soft serial settting and RS485/RS232 setting switch.

TinySine RS232/RS485 Shield for Arduino

JSumo Wing Arduino Robot Controller (w/ Arduino Nano) - RobotShop

I / O Grove Base Shield for Arduino - RobotShop

IIC/I2C/TWI Serial 2004/20x4 LCD Module Shield for Arduino Uno/Mega2560 - RobotShop

Arduino Expansion Shield for Raspberry Pi B+/2/3 - RobotShop

NFC/RFID Shield for Arduino - RobotShop

I / O Grove Base Shield for Arduino - RobotShop