Important reminder, if you own a domain name and don't use it for sending email.
@[email protected] The M3AAWG provides best practices for parked domains, including the recommendation to implement a wildcard DKIM signature.
*._domainkey.example.com TXT “v=DKIM1; p=”
https://www.m3aawg.org/sites/default/files/m3aawg_parked_domains_bp-2015-12.pdf