Image Lightbox, Responsive and Touch‑friendly — Osvaldas Valutis
MQtest.io — A simple tool to help identify which media queries your device responds to.
Responsive & Touch-Friendly Audio Player
Debunking Responsive CSS Performance Myths
Really Useful Resources and Tools for Responsive Web Design
Using window.matchMedia to do media queries in JavaScript
ResponsiveSlides.js
rlightbox – a jQuery UI mediabox
20 Useful Tools for Responsive Web Design
Responsive Web Design, most complete guide
25+ Latest jQuery Plugins
5 Awesome Responsive jQuery Sliders and Image Galleries
mattkersley/Responsive-Menu - GitHub
Turns any or into a for mobiles and low browser sizes
Responsive HTML images
Giving "Responsive HTML images" a go