This is a solver for cryptograms just based on the known letters. Simply enter the pattern of letters in the word - capital letters for unknown letters, and lowercase letters for known letters. Spaces are ignored.

The solver assumes that a capital letter cannot map to the same lowercase letter, as is common in cryptogram puzzles.

The word list is taken from Google Books Ngrams, specifically the 1-grams from the 20200217 release.

The source code is available on GitHub. See my writeup of this project.