Chatfuel - Chatfuel is the best bot platform for creating an AI chatbot on Facebook.
draw.io - Online diagramming application
Landbot - An intuitive no-code conversational apps builder that combines the benefits of conversational interface with rich UI elements.
LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
ChatBot - Easy to use chatbot platform for business
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.