Moqups - The most stunning HTML5 app for creating resolution-independent SVG mockups, wireframes & interactive prototypes for your next project
Plant - Version control app and plugin for Sketch
Balsamiq - Balsamiq. Rapid, effective and fun wireframing software.
Invision - Prototyping and collaboration for design teams
FOLIO - Simple version control app for designers based on Git
UXpin - Design is really about solving problems. UXPin is the UX Design Platform that gets that right.