Balsamiq - Balsamiq. Rapid, effective and fun wireframing software.
Invision - Prototyping and collaboration for design teams
Pencil - Pencil is an animation/drawing software for Mac OS X, Windows, and Linux.
Zeplin - Collaboration app for UI designers & frontend developers
Moqups - The most stunning HTML5 app for creating resolution-independent SVG mockups, wireframes & interactive prototypes for your next project
Webflow - Build dynamic, responsive websites in your browser. Launch with a click. Or export your squeaky-clean code to host wherever you'd like. Discover the professional website builder made for designers.