Thomas Jefferson, maybe Thomas Paine, Ben Franklin, MLK Jr., maybe Robert E. Lee, possibly James Madison, possibly John Paul Jones, possibly Teddy Roosevelt, Frederick Douglass
Abigail Adams for her gentle guidance of John Adams and maybe Elenor Roosevelt, as well, maybe Harriet Tubman, Clara Barton, maybe Mary Harris "Mother" Jones
Thomas Edison, maybe the Wright Brothers, Grace Hopper, Henry Ford, maybe George Eastman, maybe Alexander Graham Bell, possible the Woz, Andrew Carnegie, Enrico Fermi & Oppenheimer, maybe James Watson adn Francis Crick.
Louis Armstrong, Charlie Christian and Benny Goodman, Miles Davis, Muddy Waters, John Lee Hooker, Bo Diddley, possibly the Chess brothers.
EA Poe, John Steinbeck, Ernest Hemingway, Twain/Clemmens, maybe Emily Dickenson. Frank Lloyd Wrigt, HD Thoreau
Nelly Bly, Jacob Riis, Lewis Hine
Plenty more. That's all I can think of right now.