An Inertial Measurement Unit or IMU sensor uses a combination of accelerometers, gyroscopes and magnetometers to report on the force, angular rate and orientation of a body in motion.
Adafruit's "learn" pages include a comparison
of the following boards:
3 Axis MEMS Gyroscope - ST
3 Axis MEMS Gyroscope - NXP
9 Axis* MEMS Sensor (Accel + Mag + Gyro) - ST
9 Axis* MEMES Sensor (Acce + Mag + Gyro) - ST
9 Axis* MEMS Sensor (Accel + Mag + Gyro) - Invensense
6 Axis MEMS Sensor (Accel + Gyro) - Bosch (Used in the BNO055)
from Adafruit
on Wikipedia