Dialogflow - Conversational UX Platform. (ex API.ai)
Jotform - Free Online Form Builder & Form Creator
Octane AI - Octane AI offers tools to create a bot and engage customers and audience via messaging.
Typeform - Create beautiful, next-generation online forms with Typeform, the form & survey builder that makes asking questions easy & human on any device. Try it FREE!
Botpress - Open-source platform for developers to build high-quality digital assistants
Tally.so - The simplest way to create forms, for free.