Many cards from the following sets are not recognized by the decklist system:

• KLD
• JOU
• KTK
• NEO
• M20

Just for example, Bomat Courier from the basic Pioneer burn challenger premade deck, is not recognized by the decklist system.

The same missing sets/cards are fully recognized by the Gatherer, Magic Online, TappedOut, MTG Print, and Cockatrice.

I appreciate that this project is a labor of love. If someone can help to validate the card database for completeness, that would be super.