Collectible coins encompass a variety of types, including patterns, trial coins, and specific denominations such as the three-cent piece. The three-cent coin, issued by the United States in several formats, was introduced in 1851 and later produced in silver and nickel versions. Patterns and trial coins, like those from 1874, are experimental pieces created to test designs or compositions, often not intended for circulation. These items are highly sought after by numismatists due to their rarity and historical significance, particularly those linked to notable years or designs.