PostGrid has been great for automating our insurance mails for our client
Lob - A simple API to integrate print & mail solutions into your applications.
Newsletter Guide - A 201 guide for taking your newsletters to the next level
Postalytics - Automated direct mail software that’s faster, smarter & better. Postalytics sends personalized direct mail from your CRM and analyzes delivery & response.
Newsletters by Refind - The easiest way to email a link digest to your fans
AmazingMail - Business print-mail solution
Newsletter Crew - Podcast, blog, and community for newsletter creators.