Forms On Fire - Forms On Fire provides a complete, customizable mobile forms and workflow system that is reliable and secure, works offline or online.
draw.io - Online diagramming application
Pipefy - Pipefy is a process management software that empowers anyone to create and automate efficient workflows on their own without code.
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.
ProcessMaker - ProcessMaker is an easy to use BPM and workflow software solution. It is used to design, automate, and deploy business processes of any kind.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.