Afilnet is one of the best SMS provider in the market, we have been working with this company for the last 10 years, and we're really happy with the service and support given.
Textlocal - Textlocal is an app that allows for individual and group texting. It is designed for businesses that have employers and employees who need to communicate with each other, making it easier to announce group meetings and special announcements.
Pony Express HQ - Pony Express HQ is an SMS text message marketing for small businesses, real estates, clubs, communities, dispensaries or non-profits. Send and receive text messages and images online with the large group of customers. Group texting app no reply all.
BulkSMS - SMS messaging service provider offering two-way SMS communication services.
Releans - Communication platform for Messaging and Chatbots
Twilio - Brings voice and messaging to your web and mobile applications.
Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates