Miniature Mail - Little letters printed on demand and sent in tiny envelopes.
ToutApp - Tout streamlines your email workflow with templates, email tracking, and mail merge.
MailThis - Send mail from your computer
Salesforce Sales Cloud - Cloud-based CRM & Sales Automation
The Simple Postcard - Text a photo to mail it as a postcard
SalesLoft - The simpliest way to build the most accurate and targeted lists of leads on the internet