Mailchimp
MailChimp Email Marketing and Email List Manager
Sendgrid
Delivering your transactional and marketing email through one reliable platform.
Campaign Monitor
Campaign Monitor makes it easy for you to create, send, and optimize your email marketing campaigns.
Hunter
Hunter is the easiest way to find professional email addresses. Give a domain name and get the list of all the emails related to it found on the internet.
Reallygoodemails
The Best Email Designs in the Universe (that came into my inbox)
Htmlemail
Transactional email templates for notifications, newsletters, receipts, welcome emails, ready to ship with your email service provider.
Good Copy
Good Copy • Email copy from great companies
Rivalexplorer
Search for any brand and dive into their marketing program with Rival Explorer
Foundation for Emails
A Responsive Email Framework from ZURB