Foot drop is one of the most common causes of movement disorder. Various designs of ankle foot orthosis (AFO) have been developed in the last few decades. These devices aim to reduce the impact of impairments in the lower limb neuromuscular motor system on gait. Existing AFO devices include passive devices with fixed and articulated joints, semi-active devices that modulate damping at the joint, and active devices that make use of a variety of technologies to generate power to move the foot. This paper reviews a variety of designs with their relevant actuating mechanisms, control strategies, characteristics, advantages, and drawbacks with a futuristic intelligent ideal AFO.