draw.io - Online diagramming application
ProntoForms - ProntoForms is a mobile business solutions application, converting paper forms onto any tablet or mobile device.
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.
Safety Culture - SafetyCulture is the operational heartbeat of working teams around the world. Its mobile-first operations platform leverages the power of human observation to identify issues and opportunities for businesses to improve everyday.
PlantUML - PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams.
GoFormz - GoFormz provides a complete mobile forms and reporting solution.