L293D Motor Shield

The L293D V1 Motor Shield can drive up to 4 DC motors at voltages from 4.5 – 25V and at currents of up to 1.2A peak (600mA continuous) per motor with speed and direction control.

The module can also support up to 2 stepper motors.  Each stepper motor takes the place of 2 of the DC motors, so you can run 2 stepper motors or 1 stepper motor and 2 DC motors or 4 DC motors.

The shield also technically supports 2 servo motors for which there are two 3-pin headers on the module.  Unfortunately it powers the servo motors directly off the Arduino 5V which is usually not a great idea.  Doing so can overheat the Arduino on-board 5V regulator as well as induce electrical noise into the Arduino 5V power causing intermittent problems that are difficult to troubleshoot.  On the plus side, it does have a 100uF capacitor on these power pins which does help somewhat.  If using this feature, use only with small servos like the SG90 and keep an eye out for any issues.  As another option, the traces to the 5V center pins on the servo headers can be easily cut and rewired to a separate 5V power source or the motor source if powered off of 5-6V.