Subscribe by Email template customizations

I was wondering if you have template customization samples for customizing/overriding Subscribe by Email email templates (for the header, footer, body and post). We currently have over 1,000 subscribers on our website and are looking to enhance the email template from the general default to look much better and if possible, add links to other pages, posts or categories on our website. I would deeply appreciate some help or pointers with how to make this work.
Thanks and thumbs up for the great work you guys are doing.