Real estate, heavy industry (such as automobile and machinery manufacturing), steel, aviation, high-tech products (such as computers and software), finance (banks, financial derivatives such as stock futures), agriculture (exporters of various crops), military, movies and food. The United States is a developed country, and its pillar industries are basically high value-added industries or high-tech industries.
The above are just industries with obvious gaps. In fact, as a developed country, no industry in the United States is at the forefront of the world.