Matt Denton has a 5-part series on YouTube of him building a D-O droid from Star Wars.
For the brains, Matt used an Arduino MKR-W1010, MKR Proto Shield, MKR-IMU inertial measurement shield, and MKR motor shield. For the sound board, he employed an Adafruit Audio FX Sound Board. For servos, he used Lynxmotion and Dynamixel.
H/t Maker Update