Motor Shield
You can get extra 8x 3Amp Servo motors and 4x 2Amp DC motors. All connected to just one port, so you still have the rest of Tokymaker's outputs available!
It has some LED in every DC output to show the direction and speed of the motor. This means you don't need to plug the motors to do some tests first. π
The batteries can be 3.7, 7.4 V, or 12 V and it will power Tokymaker as well.