Porterhouse - Send mass iMessage and SMS texts from your existing number with a single click!
WhatsMany - Send personalised WhatsApp messages in bulk
LoopMessage - LoopMessage is a perfect macOS tool for personalized mass messaging via iMessage/SMS, WhatsApp, Facebook Messenger, Telegram, Viber, and Skype.
Texted.io - Send text blasts to groups, receive individual replies
Promote Route - A Better WhatsApp™ Experience
Rocket for WhatsApp - WhatsApp marketing chrome extension