There are many standards for lifting equipment, most of which are concensus standards. Some have become law through OSHA adoption.
DOE-STD-1090 is a good reference which lists many of the other standards.
Which standard you need may depend upon what sort of lifting eauipment you are interested in (cranes, slings, forklift trucks, etc,), and what you are lifting (personnel, nuclear materials, steel, etc).