MagnifierRentgen is a simple, lightweight, responsive magnifier hover plugin. (magnifying glass effect)
Magnifier.js is a Javascript library enabling magnifying glass effect on an images.
Features:
mlens is a jQuery plugin that simplifies creating this magnifying glass functionality so much.
It has some parameters like the shape of the lens (circle or square), lens size and the options for customizing the border.
GSInnerZoom is a jQuery plugin that permit you to do an inner zoom or magnifier inside an image.