L293D Motor driver
This chip enables you to take 4 outputs and turn them into 2 that can be reversed.
Note that the chip can get quite warm, but it is designed for that.
You can control 2 motors in both directions instead of 4 in only one direction.
There is a 1.5V voltage drop within the L293D driver chip.
If you run both motors and servos on the same circuit, your servos will allways get 1.5V more than the motors - and typically you would want it the other way around!