Jasmin SMS Gateway - Jasmin is a very complete open source SMS Gateway with many enterprise-class features such as:
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
Bulk SMS Services - Sending Bulk SMS to the customers will engage the customers with your business and new offers.
HubSpot - Grow Better With HubSpot: Software that's powerful, not overpowering. Seamlessly connect your data, teams, and customers on one CRM platform that grows with your business.
MyTask - MyTask is a centralized platform designed for office management, invoice management, and work management that allows a business to have the required service agility.
EZ Texting - EZ Texting provides SMS marketing solutions to businesses of all sizes.