Dialogflow - Conversational UX Platform. (ex API.ai)
Zendesk Answer Bot - Chatbots
Octane AI - Octane AI offers tools to create a bot and engage customers and audience via messaging.
Aivo - Skyrocket your Customer Service and Sales KPIs with a Chatbot powered by Artificial Intelligence. Give time back to people.
Botpress - Open-source platform for developers to build high-quality digital assistants
Tars - TARS enables users to create chatbots that replaces regular old webforms.