Collectible coins encompass a wide range of categories including historical pieces, commemoratives, and patterns. The United States mint produced various coins like the 1860 PH10c, which is a pattern coin. Pattern coins are experimental pieces created to test new designs or compositions before official minting. The 1860 PH10c specifically features an innovative design that was never adopted for general circulation, making it highly sought after by collectors due to its rarity and historical significance.