PostGrid has been great for automating our insurance mails for our client
Lob - A simple API to integrate print & mail solutions into your applications.
Newsletters by Refind - The easiest way to email a link digest to your fans
Postalytics - Automated direct mail software that’s faster, smarter & better. Postalytics sends personalized direct mail from your CRM and analyzes delivery & response.
Medium Newsletters - A new way to connect with readers
AmazingMail - Business print-mail solution
Newsletter Operating System - All-in-one dashboard to launch & grow your newsletter