Zoho is the only one I know that still offers free email with custom domains, but with limited number of users - https://www.zoho.com/mail/custom-domain-email.h

Zoho is the only one I know that still offers free email with custom domains, but with limited number of users - https://www.zoho.com/mail/custom-domain-email.html https://www.zoho.com/mail/custom-domain-email.html