The Dobot Magician is a very interesting educational robot capable of 3D printing, laser engraving, picking & placing items, and performing other tasks. With the Dobot Conveyor Belt, you can do more with it. It has adjustable speed. It also comes with a distance and color sensor.
The Conveyor Belt has max payload of 500g and max speed of 120mm/s. You can find out more about it here.