Risks of serious injury or death exists while using a Onewheel. Always ride with caution!
Always ride with a helmet on. Skateboard helmets are a good option for low-speed impacts. Moto helmets can offer better protection, especially at higher speeds and on roads.
Helmets that prevent you from easily looking at your feet should be avoided.
The Triple 8 Gotham helmet has a unique style and is both CPSC Bike and ASTM Skate safety certified to protect from a variety of impacts.
Glasses or Visor
Dust or insects in your eyes at high speed can easily cause a fall resulting in serious injury. As such, eyes protection is recommended.
Wrist guards and Gloves
I like Pearl Izumi Men's Thermal Conductive Glove ($14) because they're thin, wind resistant, and work on touch screens.
More expensive, but offer great protection: Demon United Flexmeter Wrist Guard ($55) very comfortable, easy to take off/put on.
These work great as well. They leave the fingers open to access your phone while providing great wrist protection. They are easy to put on and take off. Triple 8 Hired Hands (Black) https://www.amazon.com/dp/B003BAJKVQ/ref=cm_sw_r_cp_apip_EaEj6312twh4X
Clothing is optional on the Onewheel. With that said, clothing can provide some protection to your skin in the event you get served the shit platter. Choose what's comfortable and allows for some movement.
Generally speaking, flat soled shoes are best. Nike SB is a great brand, as well as any other skate shoe.
The Reebok Nano 6 has been a great shoe for riding the onewheel. They are lightweight and allow your toes to open up and feel the board. They are great for running out nosedives.