Never Email Certain Addresses or Domains
Removes addresses and whole domains on your suppression list from every outgoing email, such as bouncing inboxes or people who asked not to be contacted, and skips emails left with no recipient.
Snippet Library
Email snippets for WordPress
Snippets for the emails WordPress sends: change the sender name and address, add a Reply-To header, send HTML email and turn off notifications you do not need. For site owners who want their messages to arrive and look right.