UXpin - Design is really about solving problems. UXPin is the UX Design Platform that gets that right.
Invision - Prototyping and collaboration for design teams
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.
Balsamiq - Balsamiq. Rapid, effective and fun wireframing software.
Moqups - The most stunning HTML5 app for creating resolution-independent SVG mockups, wireframes & interactive prototypes for your next project
Zeplin - Collaboration app for UI designers & frontend developers