The panel on the left side of the RViz is known as the Displays panel, which contains a list of display plugins for RViz and their properties. These display plugins are used to visualize different kind of ROS messages, mostly different types of sensor data in the RViz 3D viewport and robot model state information and their correspondence, for example, viewing images from a camera, viewing a 3D point cloud from a laser scan, the robot model, TF, and many more. The required plugins can be added by pressing the Add button on the left panel. Moreover, we can also develop specific display plugins and add them there.