Collectible coins include a variety of types such as numismatic coins, commemorative coins, and bullion coins. The United States has produced many notable coins, including the three-dollar gold coins, which were minted in limited quantities. Buffalo nickels, also known as Indian Head nickels, were designed by James Earle Fraser and were minted from 1913 to 1938, with the 1937 issue being particularly sought after, especially from the Denver mint due to its lower mintage. Collectors often seek specific years and mint marks to enhance their collections.