Patterns and Prototypes (accidental release)
- 1916 Winged Liberty (“Mercury”) dime patterns
- 1971-S Eisenhower dollar prototype
- 2000-P Sacagawea “Cheerios” dollar
Mid-year design modifications
- 1796 to 1799; 13, 15 and 16 stars on the U. S. dime, half dollar and dollar
- 1853 Seated Liberty dimes and half-dimes, with and without arrows
- 1867 Shield nickel with and without rays on the reverse
- 1883 Liberty Head nickel; with and without the word CENTS
- 1909 Lincoln cent; with and without the designer’s initials (V.D.B.)
- 1913 “Buffalo” nickels; Type I and Type II
- 1917 Standing Liberty quarter, with and without exposed breast
- Small date/large date
- 1960 Lincoln cent; small and large date
- 1970 Lincoln cent; two styles of date
- 1974 Lincoln cent; small and large date
- 1982 Lincoln cent; small and large date
- 1979-P Susan B. Anthony $1 (Near Date, a.ka. Wide Rim)
- Different placement of mintmark within the same year
- 1872 Seated Liberty Half dime
- 1875 Seated Liberty dime
- 1917 Walking Liberty half dollar
- 1942 Jefferson nickel; with and without mintmark
Conceptual design flaws (foul-up in design or in translating design to master hub or master die) (CW 11/15/21)
- Misspellings (foreign only) (CW 1/25/16, 4/18/16)
- Chile 50 Peso, with country’s name misspelled “CHIIE”
- Brazil (Brasil) 1000 Reis, 1922, with country’s name misspelled “BBASIL”
- Croatia 1 Kuna, 1994, with bird’s name misspelled “LUSCINNIA”
- Inaccurate design
- Italy 1000 Lire with outdated map borders
- Montreal $5 Olympic Coin, 1976. Runner with two left feet
- 1828 half cent; with 12 stars
- 1832 $5.00 gold; with 12 stars
- 1817 Large Cent with 15 stars on the obverse (possibly done intentionally as a political statement)
- 1804 Draped Bust dime with 14 stars on the reverse (possibly done intentionally as a political statement)
Mistakes during design modification
- 2007 Mexico 10 pesos with reversed dentils
- 2008 Chile 50 pesos with country spelled “CHIIE”
Unauthorized strikes and unauthorized issues (CW 1/20/14)
- 1913 Liberty Head nickel
- 1954 Mexico 5 centavos (small size)