Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.

Spark Mail - Spark helps you take your inbox under control. Instantly see what’s important and quickly clean up the rest. Spark for Teams allows you to create, discuss, and share email with your colleagues

Landbot - An intuitive no-code conversational apps builder that combines the benefits of conversational interface with rich UI elements.

mlist - Email newsletters, outside of the inbox

Botsify - Ever wonder if you could replace your live chat support system with a chatbot?. Its possible now with Botsify Chatbot For Website.

TL;DR Email - Send short emails & read emails as fast as you read Facebook