Bip39 seed phrase list https://files.fm/u/2eemhhak2q#design BIP85: A more recent proposal enabling the deterministic derivation of multiple BIP39 mnemonic seeds from the master seed. For words that have only 3 letters, there isn't any 4th letter. As an example Together with the word “add”, there won't be any much more letters https://cutt.ly/urYc5rW7