jQlouds is a jQuery plugin that let's you create clouds on the fly. There are some options to customize plugin.
Stackbox is a jQuery plugin for creating stackable modal boxes. It's also easy to customize using CSS / LESS.
CSS3 Animate It is a lightweight plugin to animate elements on to the page when they come into view.
gifplayer is a customizable jQuery plugin to play and stop animated gifs.
ProBars is a stylish progress bars that animate as they enter the viewport.
waitMe is a jQuery plugin for easy creating loading CSS3 animations. Plugin use css3 animation, and works on all browsers and IE10+.
Velocity is a jQuery plugin that re-implements
$.animate() to produce significantly greater performance (making Velocity also faster than CSS animation libraries) while including new features to improve animation workflow.
LetterFx is a a jQuery plugin to apply animated visual effects to text - letters, words & custom patterns.
LetterFx works by temporarily injecting markup into the text of an
$("element") and sequentially adding & removing transition-based CSS classes.
Forkit.js is an experimental animated ribbon which reveals a curtain of additional content.
ClassyLoader is a jQuery plugin that lets your add beautiful and animated loaders to your website.