Every piece of hardware Valve has made over the years

Release Year: 2015
Valve's first attempt at desiging hardware. It tried to achieve a game console-like experience but with the flexibility of a PC and Steam games. Due to limited game compatiblity and the fact that the production was handled by third party companies such as Gigabyte and Alienware, the Valve Steam Machine was a failure.
Year Discontinued: 2019

Release Year: 2015
Launched with the Steam Machine was the Steam Controller. Its main feature was the use of two circular trackpads, allowing for extra control inputs. While the hardware was good, the sales were not, and the Steam Controller was discontinued.
Year Discontinued: 2019

Release Year: 2015
The Steam link box connects to your TV, and allows you to play on your computer from the confort of the living room. The Steam link box wirelessly streams the game running on your computer to your TV. Sales were also low, and one day, they stopped manufacturing anymore.
Year Discontinued: 2018

Release Year: 2019
Can Valve recover after 3 product fails? Yes! Yes they can. The Valve Index is a PC virtual reality kit, and is one of the best in class, with high resolution, high refresh rate screens, spatial audio, and flawless tracking. Paired with the Valve index is the Valve Knuckles controller, which tracks all five fingers for the first time, allowing for immersive hand tracking. While its entry price is rather high at 1000 dollars, the experience is worth the money. Indexes are still being made and it is unlikely that they will be discontinued unless an Index 2 is made.

Release Year: 2021
The Steam Deck is a spirtual successor to the Steam Machine, with a twist -- instead of being a desktop computer, it is a handheld! Reservations opened in July 2021, and the first units started shipping in Feburary this year. This time, they have a trick up their sleeve, and it is Proton, which greatly improves the game compatibility compared to its predecessor.