menu-aim is a jQuery plugin for making responsive mega dropdowns like Amazon's.
FlexSlider is an awesome, fully responsive jQuery slider toolkit.
Modules can be linked based on contextual parameters like viewport size and element visibilty making Conditioner your perfect Responsive Design companion.
Frappé Charts is a GitHub-inspired simple, responsive, modern SVG charts library with zero dependencies.
Scalable makes the elements scalable to fit inside the container area.
Lity is a ultra-lightweight, accessible and responsive lightbox plugin which supports images, iframes and inline content out of the box. It requires jQuery or Zepto
jcSlider is a jQuery plugin to create responsive slider with CSS animations.