Collectible coins encompass a variety of types, including patterns and trial coins, which are sometimes produced to test designs or minting processes before standard coins are released. The United States, particularly with coins such as the fifty-cent pieces (often referred to as half dollars), has a rich history of such collectibles. In 1822, certain patterns were created as trial coins, displaying unique designs that differ from their production counterparts. These items are highly sought after by collectors due to their rarity and historical significance.