Reserved powers are retained by state governments when not explicitly given to Congress. This is the tenet of the Tenth Amendment of the U.S. Constitution.
Under the 10th Amendment, State's Rights are, not were, the idea that any right not written in the Constitution is given to the states. Well, not given to, rather retained by
Makran - princely state - ended in 1955.
Kharan - princely state - ended in 1955.
Kharan - princely state - was created in 1697.
Princely State of Mysore was created in 1799.
Chitral - princely state - was created in 1585.
Chitral - princely state - ended in 1969.
Swat - princely state - ended in 1969.
Swat - princely state - was created in 1849.
Nagar - princely state - ended in 1974.
Patna - princely state - ended in 1948.