Try a copy of " U.S. Coin Prices" Magazine. They give current prices of coins in various grades, and with that you can find what coins are "key" dates etc. At one time they also included the number of each coin that was minted, but not so anymore. I kept a copy from Jan 2016 just for that reason. It is a really good tool to use to find out more about what you may have found. Also to learn more about any one coin, go on the internet, and enter the type ( 1 cent, 5 cent etc.) the date and any mint mark, and anything you want to know will be there. This is really good for foreign coins as well. Hope this helps.