Sortd - Rated the #1 App for Gmail
Sidemail - The simplest way to send transactional emails. Sidemail makes sending transactional emails trivial, it's perfect for side projects, MVPs or the next big thing.
Email Architect - All-in-one system to write, manage and organize email
Mailivery - Reach the Inbox, not the spam folder.
Front - The platform for exceptional customer service at scale.
Postal - Open source mail delivery platform, alternative to Mailgun or Sendgrid