One major variety is the 1823/2 overdate error of the Coronet Head Large Cent (Penny). This coin features an 1823 date struck on top of an 1822 date which resulted in part of the underlying "2" being visible within and around the "3".
One major variety is the Unofficial Restrike of the 1823 Coronet Head Large Cent (Penny). This coin was produced by muled dies (combining dies that were never meant to be together) consisting of the 1823 obverse die and 1813 reverse die. These coins were not struck officially at the mint. Rather these broken dies were sold for iron scrap to a man named Joseph Mickley in the 1830s. Mickley acquired many of these broken dies and produced a variety of coins by muling dies and evening mixed denominations. This 1823 restrike was produced using very rusted and cracked dies which make it easy to identify. The coins were probably struck sometime in the 1860s-1870s. Some of these were even produced in silver.