The jog wheel. A must for anyone who edits video on a regular basis. Well, maybe not a “must” but definitely handy. They’re expensive, though, as evidenced by this otherwise normal keyboard that costs $272 thanks to the attached jog wheel.
You’ll have to order it from far, far away, too. All the way from Japan. As for specs, it’s a 105-key USB keyboard with a built-in three-port USB hub and the aforementioned jog wheel flanked by commonly used video editing shortcut buttons. It comes with configuration software as well, so you can remap the buttons according to your particular project.