Chatfuel - Chatfuel is the best bot platform for creating an AI chatbot on Facebook.
Dialogflow - Conversational UX Platform. (ex API.ai)
Message Me - Website to create your contact business card
Octane AI - Octane AI offers tools to create a bot and engage customers and audience via messaging.
Amazon Lex - Harness the power behind Amazon Alexa for your own conversational apps.
Botkit - Botkit is an open source developer tool for building chat bots, apps and custom integrations for major messaging platforms.