Collectible coins, such as the United States One Dollar coins and Franklin Half Dollar coins, are popular among numismatists for their historical significance and potential investment value. The One Dollar coin has seen various designs and series, including the Sacagawea and Presidential dollars. The Franklin Half Dollar, minted from 1948 to 1963, features a portrait of Benjamin Franklin and is sought after for its 90% silver content and historical appeal, especially among collectors focusing on mid-20th century American coinage.