Collectible coins, particularly those from the United States, encompass a variety of types including commemorative coins, bullion, and regular issue coins. The 25-cent pieces (quarters) are a popular choice among collectors, featuring designs that often celebrate national parks, historical events, or notable figures. Mint Sets, such as those produced in 2019, include uncirculated coins from that year, often sought after for their pristine condition and packaging, providing collectors with a complete representation of coins issued by the U.S. Mint during that time.