It depends on the strength of the worker's background, his or her country of citizenship, etc., but, assuming that the worker is not from a country with its own work visa (Australia, Canada, Chile, Mexico, and Singapore), then an L-1 intracompany transferee visa is often the fastest but where this doesn't apply, then the O-1 (which also isn't subject to an annual lottery), the E-1 and E-2 (which also isn't subject to an annual lottery), and the H-1B.