Collectible coins, particularly those issued by the United States, encompass various types including commemoratives, numismatic coins, and special issues like patterns and trial coins. The 1976 One Dollar coin, which celebrated the nation's bicentennial, featured unique designs and was part of a series that included both circulating coins and special collector's items. Patterns and trial coins are experimental strikes that are not intended for general circulation but are minted to test designs and manufacturing processes, making them particularly sought after by collectors.