Currently dark web monitoring seems to just look for emails. Some logins are not emails and there could be compromised passwords revealed on the dark web. Even google chrome will check compromised passwords in their database. There should be a way to either manually or automatically check your passwords (especially the LastPass-generated ones) on dark web. No matter how strong the password, sites will be compromised through back doors and sometimes the exploits aren't known except for these unique passwords circulating. Can be done securely by checking hash of secure passwords against hashes of exposed password.