Botsify - Ever wonder if you could replace your live chat support system with a chatbot?. Its possible now with Botsify Chatbot For Website.
Dialogflow - Conversational UX Platform. (ex API.ai)
Chatfuel - Chatfuel is the best bot platform for creating an AI chatbot on Facebook.
Octane AI - Octane AI offers tools to create a bot and engage customers and audience via messaging.
Massively - Create and deploy polished chat bots
Microsoft Bot Framework - Framework to build and connect intelligent bots.