veradeveloper

This plugin allows you to easily scroll back to the top of the page.
Documentation 
To change global settings, go to “Settings” -> “Wow scroll up”.

Wow scroll up

Simple & easy

This plugin allows you to easily scroll back to the top of the page.

PluginsPoint

Kento Scroll. Jump. Top. Is a simple and very light plugin that will take your visitors to the top of the page once they are scrolling through your page.
Plugin Features
<ul>
<li>Select from 20+ icons</li>
<li>Smooth transition</li>
<li>Easy install and active</li>
</ul>
Plugin Demo and Support: http://kentothemes.com/items/plugins/kento-scroll-jump-top/

Wow scroll up vs Kento Scroll Jump Top