I found a code that wasn't mentioned on the wikia, it's the sereal number on the negative twelve dollar bill. I posted my discovery on the negative twelve dollar bill page, but I didn't put it in the list of cryptograms page because I don't know how to use html.
Will someone who knows how to please do that?
"0239548604" when you separate the numbers into pairs (02 39 54 86 04) and then add the sum of the digits in each of the pairs (2 12 9 14 4) then put that through the a1-z26 cipher, you get the word "BLIND"