There is an accessory called a Pokemon Go Plus that apparently lets you play Pokemon Go without having to take out your smartphone out every time you want to catch Pokemon or visit a Poke Stop.
The Pokemon Go Plus bracelet links to your smartphone via Bluetooth and allows you to play Pokemon Go without having to constantly look at your phone screen.
It will blink and vibrate when you are in range of a Poke Stop, and all you have to do to collect items from the Poke Stop is press the button on the Pokemon Go Plus.
If a Pokemon is nearby, the Pokemon Go Plus will begin flashing. Simply press the button on the Pokemon Go Plus to throw a Poke Ball. You will only be able to throw a Poke Ball using the Pokemon Go Plus if you have caught the Pokemon before.
Personally I think that the Pokemon Go Plus is the perfect accessory for Pokemon Go. It has the potential to reduce accidents by people not looking where they are walking while playing Pokemon Go. Not having to keep your smartphone constantly out will reduce the chance of a robbery. Also, the Pokemon Go Plus reduces the amount of effort needed to play Pokemon Go drastically as all you need to do to play is press a button.
Read more about the Pokemon Go Plus here: https://support.pokemon.com/hc/en-us/articles/360000954814-About-Pok%C3%A9mon-GO-Plus. It can be purchased easily from stores like Amazon and Walmart.