Moqups - The most stunning HTML5 app for creating resolution-independent SVG mockups, wireframes & interactive prototypes for your next project
Magnific Popup - The greater part of Lightbox modules will completely preload a picture before showing it.
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.
jQuery Lightbox - jQuery Lightbox plugins are utilized to showcase images and other web stuff using modal dialogs.
Axure RP - The prototyping and specification software used by 87% of the Fortune 100. Beyond mockups, design interactive prototypes for business solutions, websites, and applications.
Fancybox - fancyapps.com - Fancy App Store