I’m always happy when I find a new kind of part that is cheap and easy to use with DIY electronics projects or robotics, the more standardized the better.
There’s a whole world of smart electronics and helper things in the hobby and remote control world that are great for robots and other things.
You probably already know that hobby servos are easy to control from any microcontroller like the arduino, but there are a bunch of other things that are just as easy to use. Generic motor controllers, battery systems are also equally as useful, but are sometimes hard to sort...