What generation of AirPods is the newest?

As Apple is eager to point out, not all AirPods are created equal. While all of the Bluetooth headphones are wireless, there are multiple generations of basic AirPods, and even multiple generations of the AirPods Pro and AirPods Max (sort of). There can be substantial feature differences, to the point that even at a bargain, you might not consider earlier generations worth it.