Here's one spray-on product, and Krylon also makes one.
Tread Tex Skid Resistant Coat
15-0011
Tread Tex Clear Skid Resistant Texture Coating is a clear spray coating that can be applied to interior or exterior surfaces for slip resistant safety.
This non-yellowing coating with UV protective additives, producesa tough and long wearing skid-resistant surface perfect for marine, industrial, commercial and household environments. Tread Tex can be used in hundreds of locations including stairways, floors, ladders, ramps, boat steps, walkways, playground equipment, running boards, skateboards, hand rails, porches, decks, landing and more.
One can covers about 20 sq. ft.