Slaask - Slaask enables you to set up a dedicated live chat channel on your Slack.
WhatsMany - Send personalised WhatsApp messages in bulk
JivoChat - JivoChat is a live chat that enables you to talk to visitors on your website
LoopMessage - LoopMessage is a perfect macOS tool for personalized mass messaging via iMessage/SMS, WhatsApp, Facebook Messenger, Telegram, Viber, and Skype.
Chatlio - When you have a business to run, your average instant messaging software just will not do. You need an internal presence upon which your entire team can collaborate on. Read more about Chatlio.
Porterhouse - Send mass iMessage and SMS texts from your existing number with a single click!