Lob - A simple API to integrate print & mail solutions into your applications.
ShoutOUT - All in one business texting tool to send personalized alerts, promotions, reminders, short links and marketing campaigns, for any SMEs (hotels, restaurants, education, non profits, Woocommerce, banks, healthcare, agencies, supermarkets, weddings)
PebblePost - PebblePost invented Programmatic Direct Mail® to transform real-time online activity into personalized, dynamically rendered direct mail.
ProTexting - ProTexting offers mobile marketing tools for businesses to communicate with their audience via SMS & MMS campaigns.
Squarespace Email Campaigns - Email, but pretty.
Trumpia - SMS Marketing and Marketing Automation software for Mass SMS, internal communications & emergency alerts. #1 Text Messaging Service used by Fortune 500s.