Ilya Makarov
Easy as hell jQuery plugin for video backgrounds.
jQuery Lazy – Delayed Image and Background Loader
Daniel 'Eisbehr' Kern
The fast and lightweight Lazy plugin for jQuery loads specified images and backgrounds in view after the page itself and speed up your loading time through this. Images outside of the visible area will only be loaded when the user scrolls to them in any direction. This will not only increase the page loading speed, it will even decrease your traffic.
jQuery Unobtrusive Background Image Switcher
Yuriy Davats
jQuery plugin that makes it possible to use many heavier images as full screen background slider or image slider, while minimizing their influence on load times.
Jonathon Menz
jQuery plugin for 'responsive cropping'. Dynamically crop images to fill available space without cutting out the image's subject. Great for full-screen images.
Pupunzi (Matteo Bicocchi)
This plugin let you play any public YouTube video as background of your page. It can also be used as a customized player in page.
Dynamic Drive
A large background images carousel to show large images using the versatility of CSS's background property. The carousel is adaptive to different screen sizes, plus swipe friendly to navigate.
jQuery Element Background Dimming
Andy Wermke
This lightweight plugin allows you to dim (darken) all the website but one or more user-selected elements. A frequently used eye candy for every web application.
Michael Bragg
Attach a random background image to an element from a user supplied list on page load.
Ben Plum
A jQuery plugin for smooth-scaling image and video backgrounds. Part of the Formstone Library.