There are several types of standing desks available on the market. Fixed-height standing desks are traditional standing desks that are designed to be used while standing. Height-adjustable standing desks can be adjusted to different heights, allowing the user to work while sitting or standing. Convertible standing desks can be converted from a traditional desk to a standing desk by adding a riser or platform. Treadmill desks are standing desks with a built-in treadmill, allowing the user to walk while working. Desktop risers are platforms that can be placed on top of a traditional desk, converting it into a standing desk.