Collectible coins encompass a variety of types, including commemorative, historical, and bullion pieces, often sought after for their rarity, condition, and historical significance. In the United States, the "Three Dollars" coin refers to the gold denomination minted primarily in the 19th century, while the "Shield Two Cents" coin features a unique design introduced in 1864, representing the Civil War era. Both types reflect important aspects of U.S. monetary history and appeal to numismatists for their artistry and connection to American heritage.