Replika - Your Ai friend
Dialogflow - Conversational UX Platform. (ex API.ai)
Hugging Face - The Tamagotchi powered by Artificial Intelligence 🤗
Octane AI - Octane AI offers tools to create a bot and engage customers and audience via messaging.
Zo - Tay's nicer, better behaved sibling by Microsoft
Botkit - Botkit is an open source developer tool for building chat bots, apps and custom integrations for major messaging platforms.