Lightbox libraries are used to display images, videos, iframe and other content in an overlay above the website page by dimming out rest of the web page.
Here is a list of 7 best Drupal modules that integrate various lightbox libraries into Drupal.
Colorbox is a light-weight customizable lightbox plugin for jQuery. This module is also available for Drupal 8.
The Fancybox module is the best way to incorporate the fancyBox jQuery plugin into Drupal. Display images, HTML, YouTube videos, Google maps in an elegant and aesthetic lightbox alternative.
The Lightbox2 module is a simple, unobtrusive script used to overlay images on the current page.
Shadowbox is a JavaScript modal media viewer application for viewing images, video, Flash and other content in a modal window.
Magnific popup module integrates Dmitry Semenov's Magnific Popup jQuery lightbox plugin with Drupal as a field formatter.
This module integrates YoxView, a free Lightbox-type media and image viewer jQuery plugin into Drupal.
The CssBox is very light-weight module that works as other lightbox modules but it does not use jQuery or JavaScript for that.