How many different US 50 cent coins are there?

Flowing Hair (1794-1795)

Draped Bust (1796-1807)

Capped Bust (1807-1839)

Seated Liberty (1839-1891)

Barber (1892-1915)

Walking Liberty (1916-1947)

Franklin (1948-1963)

Kennedy(1964-)

In addition, special versions of the Kennedy design were struck in 1975 and 1976 as part of the Bicentennial celebrations.