Dialogflow - Conversational UX Platform. (ex API.ai)
IBM Watson Assistant - Watson Assistant is an AI assistant for business.
Api.ai - Api.
Aivo - Skyrocket your Customer Service and Sales KPIs with a Chatbot powered by Artificial Intelligence. Give time back to people.
Messenger Platform - Discovery, chat extensions, and richer experiences
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.