opsdroid - An open source chat bot framework written in python.
Hubot - Hubot is a standardized way to share scripts between everyone's robots.
BuildMaster - BuildMaster Software is an application release automation software that also specializes in release management. It was designed by Inedo, a software development company. Read more about BuildMaster.
Dialogflow - Conversational UX Platform. (ex API.ai)
Botpress - Open-source platform for developers to build high-quality digital assistants
Microsoft Bot Framework - Framework to build and connect intelligent bots.