Yellow Rubber Wheels with a diameter of 3.7cm.

The TinkerKit Arm is a fully operational Robotic Arm, controlled via Arduino. It can be assembled in a variety of ways for various tasks, such as moving objects. You can also attach a camera or solar panel. There are many ways Arm can extend the range of your devices.

SparkFun Wireless Motor Driver Shield

Full size 2 wheels package with rubber base - 125 mm in diameter and 60 mm wide .

The MeArm Classic Maker Kit version is an easy-to-build Kit Robot Arm designed for kids and adults alike to learn about technology, engineering and programming. It was expressly designed to be easy to build (+11 years old) and easy to use. You can use any control board you like. It also gives you the freedom to use any type of arm control that will connect to your board, be it a joystick, keyboard, levers, or slider potentiometer. The only tool you'll need to build it is a hex wrench, and one is included in the box.

This Robot Kit does not need welds or cables to mount it, you will only need one screw.
Bit:Bot can be used by children and adults and this Kit allows you to explore and encode Micro:Bit using one of the available languages (all features are not supported in all languages).

This black polyurethane wheel measures 84mm in diameter and 24mm in width and works with 608 rpm bearings.

Pololu Wheel 80×10mm Pair - Black

Pololu Wheel 60×8mm Pair - White

Pololu Wheel 42×19mm Pair

Pololu Aluminum Scooter Wheel Adapter for 4mm Shaft

The Pack of 4 Black Wheels is a product specially designed for the construction of robots stands.

Which wheels should your robot car use? How about the Wheel of Mecanum! The Mecanum Wheel is an omnidirectional wheel design for a land vehicle to move in any direction, such as going straight, obliquely, horizontally, line S and turning at any angle with zero radius.