I would also love to have the option to set a footer for all email templates, this is required by GDPR.
Footer at bottom of automated emails? - #2 by awesomerobot works only for the HMTL version of the email, not the plain text view.
Sure I could apply it to all of the templates but as soon as a new email template is added to Discourse, I would miss to add it so a base footer for all templates would be amazing.