Most pennies from 1943 are made of zinc-coated steel due to shortages of copper during WWII.
This coin is easily recognizable by the doubling of the lettering and date on the obverse side. It's quite rare and can be very valuable.
There is a rare variety of the 1972 Eisenhower Dollar where the reverse design is missing the "S" mintmark.
In 1982, the U.S. Mint did not produce dimes for circulation in Philadelphia, but a few were accidentally struck.
Some 2004 Wisconsin state quarters have an extra leaf on the ear of corn, making them highly sought after by collectors.
In a limited run of the 2005 Westward Journey series of nickels, some were struck with a die gouge that looks like a spear going through the bison's back.
Some of the 2009 quarters have low mintage numbers and are valued by collectors.
This is a recent error where a strong doubled die is visible on the reverse side of some 2014-D Arches National Park quarters.