Directories are the websites that host business details in relevant categories. Directories used to work as link farming sites. Due to this issue, Google started penalizing those websites involved in directory submissions.
Directory submissions have been irrelevant now.
Alternates of Directory Submission
Classified websites and craigslist are the best alternatives to directories. A classified website actually ranks and sends traffic to the listed businesses. You maybe won’t get the backlink advantage but certainly, get the real traffic and leads.
List of some good classified websites