Axure - The most powerful way to plan, prototype and hand off to developers, all without code. Download a free trial and see why professionals choose Axure RP 9.
UX Archive Animated - iOS apps animated user flows
Balsamiq - Balsamiq. Rapid, effective and fun wireframing software.
Page Flows - User flow design inspiration for mobile & desktop
Moqups - The most stunning HTML5 app for creating resolution-independent SVG mockups, wireframes & interactive prototypes for your next project
UI Patterns - Level up with interactive mobile design patterns