Collectible coins include various types such as commemorative, historical, and bullion coins. The United States has produced several series of collectible coins, including the 50 cent denomination, which has been released in different designs over the years. Modern commemoratives, introduced in 1986, celebrate significant events, anniversaries, or individuals, appealing to collectors and investors. These coins are often minted in limited quantities and can feature various materials and designs, enhancing their desirability among collectors.