Collectible coins often encompass various types, including commemorative coins, bullion coins, and numismatic coins. The United States offers a wide range of collectible coins, including the 1-cent coin (penny), which has historical significance and various designs. Proof sets, such as the 2020 Proof Set, feature specially minted coins that provide higher quality with a mirror-like finish and are intended for collectors. These sets typically include coins from different denominations, often capturing significant moments in U.S. history or honoring notable themes.