There are other modules to make the drone even smarter such as GPS, Wi-Fi module (for example, ESP8266), battery checkers, and range booster antennae, and so on.
Some modules to make the drone smarter
Power distribution board
The power distribution board of the drone allows the components of the drone to get a proper current and draw a perfect voltage. We will have four ESCs; we can buy a power distribution board to deliver the proper current to all the ESCs. The following picture is a power distribution board of a drone: