Wisconsin Extra Leaf Error (2004): This error features an additional leaf on the corn stalk on the reverse side of the Wisconsin state quarter.
Minnesota Double Die Error (2005): The Minnesota state quarter is known for a variety of "Double Die" errors, where extra trees appear on the reverse side. The doubling can vary in appearance and location, with more pronounced errors being especially valuable.
Delaware Spitting Horse Error (1999): On some Delaware state quarters, there’s a die crack on the reverse that appears to extend from the horse's mouth, resembling a "spitting" motion. This unique error makes the coin highly collectible and valuable.
Arizona Extra Cactus Error (2008): On certain Arizona state quarters, an extra cactus leaf appears covering the designer’s initials. This die chip error is unusual and increases the coin's value, especially in well-preserved conditions.
Kansas In God We Rust Error (2005): This error occurs due to a grease-filled die, causing the “T” in “Trust” to appear faint or missing, resulting in “In God We Rust.” This striking error is popular among collectors, boosting the coin's value.
Oklahoma Ghost Error (2008): The Oklahoma state quarter features a "Ghost" error, where the design appears faint or partially missing due to a weak strike. These errors can make the quarter worth significantly more than its face value.
South Carolina Extra Branch Error (2000): Some South Carolina state quarters feature an extra branch extending from the tree on the reverse side due to die wear or a die clash. This error is rare and can increase the value of the quarter considerably.