Baker Numismatics
Photographic image library of coins with doubled dies, repunched mintmarks, over mintmarks, and repunched dates.
Canadian Error Coins
Information and some images of circulating errors, including an overview of die varieties. Site in English and French.
Collecting Error Coins
Just as nearly every family has its black sheep, virtually every coin series has its failures. These are known as errors or mis-struck coins, and have a following all their own.
Combined Organizations of Numismatic Error Collect
National numismatic organization devoted to error and variety collectors.
Error Coins Magazine
Monthly magazine devoted to error coin collecting. Available by subscription.
Error World
Internet club devoted to error and variety coinage of all kinds.
Israel Error Coins
The site focuses on Israeli error coins but also features Canadian, U.S. and others. See bi-metallic errors, coins struck on scrap metal, and others.
Jason's Error Coins
Images of a collection of error coins. Wheat cents, Mercury dimes and other assorted.
Rotated Die Coin Census
Census for US coins with major die rotation of 90 degrees to 180 degrees. Includes fake error detection and measurement indices.
Silver Dollar VAMs
Detailed information on silver dollars, specifically Morgan and Peace Dollar die varieties known as VAMs.
World Error Coins
Describes and illustrates dramatically mis-struck foreign coins. Includes information on recognizing various types of error coins as well as articles on how to get started collecting them.