Gaming accessories, especially first party gaming accessories that were stupid, useless, or way too niche.
Nintendo 3DS Circle Pad Pro
Added a second analog stick to the 3DS, communicated with it through the infrared port of all things. Not many games used it but the ones that did benefitted greatly. The New 3DS incorporated this into its design kinda haphazardly with a little trackpoint style nubbin.
Nintendo 3DS XL Circle Pad Pro
Similar to the above but this one was for the 3DS XL. Exclusive to Japan so much rarer.
Nintendo 3DS NFC Reader/Writer
A weird little thing that again, used IR communication. This was made to support amiibo on the vanilla 3DS, 2DS and 3DS XL because they’d added an NFC reader to the New 3DS.
Nintendo amiibo
They’re still making and supporting these. They were made to latch onto the toys-to-life thing that Skylanders and Disney Infinity created. They’re largely useless as anything other than a collectible figurine. They sometimes unlock something in games, but usually they just sit on a shelf.
Nintendo NES Speedboard
Just look at this thing. How on earth is this supposed to make you better at playing? It looks awful.
Sega Activator
An early attempt at motion control that just doesn’t work. A bunch of invisible IR beams get disrupted by stepping over them.
Xbox One Kinect
Originally mandatory for using an Xbox One, quickly discontinued when they realized no one wanted anything to do with it. Also it’s based on a different and worse technology than the original Xbox 360 Kinect.