ProTexting - ProTexting offers mobile marketing tools for businesses to communicate with their audience via SMS & MMS campaigns.
SMSGlobal - SMSGlobal offers a web-based platform and API's enabling businesses to send mass SMS's.
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)
Tatango - Tatango is a mobile messaging platform for agencies.
Trumpia - SMS Marketing and Marketing Automation software for Mass SMS, internal communications & emergency alerts. #1 Text Messaging Service used by Fortune 500s.
Postscript - Like Mailchimp for SMS