Invision - Prototyping and collaboration for design teams
UXpin - Design is really about solving problems. UXPin is the UX Design Platform that gets that right.
Atomic - The fastest way to design beautiful interactions
Moqups - The most stunning HTML5 app for creating resolution-independent SVG mockups, wireframes & interactive prototypes for your next project
Pixelapse - Visual version control and collaboration workflow for open source and private design projects.
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.