UXpin - Design is really about solving problems. UXPin is the UX Design Platform that gets that right.
Quick Diagram - A tool for generating diagrams and flowcharts from text.
Moqups - The most stunning HTML5 app for creating resolution-independent SVG mockups, wireframes & interactive prototypes for your next project
draw.io - Online diagramming application
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.
Superdocu - Onboard people at scale, stay compliant.