This accessory is included with every Nintendo Switch that ships.
But we never know what to call it.
Usually in our household we'll be like "can you pass me the grip thingy that the controllers dock into for single-player mode?"
That's getting a bit tiresome. Sure, we could give it our own name ("black handle Playstationy whosamawhatsit") but... I have to believe that the designers of this accessory gave it a name. And that name is probably more accurate and dignified than whatever label we might conceive of.
So, what is this thing called?