Are there any entities required to have patent attorney representation?

Yes, juristic entities (e.g., organizational assignees) must be represented by a patent practitioner. As stated in MPEP 401:

An applicant who is a juristic entity must be represented by a patent practitioner.

This requirement ensures that organizations have proper legal representation when navigating the complex patent application process. Individual inventors and joint inventors, however, may represent themselves if they choose to do so.

For more information on juristic entity, visit: juristic entity.

For more information on organizational assignee, visit: organizational assignee.