Collectible coins can encompass a wide range of types, including historical, commemorative, and error coins. Notably, the 1913 Liberty Head nickel is one of the most famous and sought-after coins in American numismatics, originally struck in a limited quantity, with only five known specimens. Slugs, such as the Jankovsky coins, may refer to irregular or non-standard coins often produced as curiosities or for private minting, deviating from official currency standards. Collectors value these items for their rarity, historical significance, and unique design features.

Item Denomination Series Year Mint
(1913) Brass J-213 Slug Ms Other / Varied Slugs - Jankovsky 1913 Unknown