One major variety is the 1829 Coronet Head Large Cent (Penny) with Large Letters on the reverse of the coin. The letters around the rim of the reverse are larger. The difference between the Large Letters vs Medium Letters is depicted below in the example comparison image of both coins. In some cases the letter "A"s will be filled in on the Medium Date Variety.
One major variety is the 1829 Coronet Head Large Cent (Penny) with Medium Letters on the reverse of the coin. The letters around the rim of the reverse are smaller. One of the most notable features is the three letter "A"s in the words UNITED STATES OF AMERICA. In some cases the inside of the "A" will also be filled in as depicted below. The last "A" in the word "AMERICA" is also slightly doubled and parts of the underlying "A" can be seen just to the left of the letter.