The Drone Controller (also called Transmitter Radio or Radio for short) is what allows you to control the drone remotely.
There are different protocols that are not cross-compatible, so make sure you pick the right one for your drone!
TX12 MKII ExpressLRS EdgeTX
$99.99
DJI RC Motion 3
$99
AG01 CNC Hall Gimbal Set
$129.99
Rotor Riot Lanyard
$7.99