Parts
There are many different types of parts that can be used in vex robotics.
Structure
This category includes the parts that make up the body of your robot.
You can learn more about the structural components here.
Motion
This category has everything that is designed to help with making things move on the robot. This includes things like wheels, axles, gears, and chain. However, it does not include actuators like motors and pneumatic pistons, which are in the electronics and pneumatics categories respectively.
You can learn more about the motion components here.
Electronics
This category of parts includes things like batteries, the robot's brain, and motors.
You can learn more about the electronic components here.
There are also several types of sensors that can be used, which you can learn about here.
Pneumatics
This category of parts includes things components that use air to create motion.
You can find more about pneumatic components here.