Nazmul Islam

This plugin will add a Scroll To Up button in your site footer right. Here is very easy to setup for change color option and many more. First install the plugin and let’s see.
Features: 
<ul>
<li>Easy Customization</li>
<li>Super Lightweight</li>
<li>Unlimited color Selection</li>
<li>Plugin Option Panel</li>
<li>Super easy Installation.</li>
<li>Responsive for all devices.</li>
<li>All browser supported.</li>
<li>Super Lightweight, only 60 KB.</li>
<li>Unlimited colors.</li>
<li>Works with every version of wordpress.</li>
<li>24/7 Support for free</li>
</ul>
Wanna see how it’s works? Click here : <a href="http://lumianszone.com/plugins/lz-scroll-up/" rel="nofollow ugc">LZ Scroll Bar Up Demo</a>

LZ Scroll Bar

LZ Scroll Bar Up is an awesome, Super lightweight plugin for your wordpress website

Jaspreet Chahal

This plugin gives you granular control on styles and positioning of your ‘Scroll to top’ text. Many variety of easing animations supported. 
You can also choose when you would like the Scroll to top becomes active. 
You can enable or disable this plugin just by setting ‘Enabled’ under Settings > JCWP Scroll To Top > Enabled to “No”
You can follow me on Twitter https://twitter.com/jschahal or 
like my facebook page http://www.facebook.com/jaspreetchahal.org to get updates on some not so exciting things that I do.
Visit my site http://jaspreetchahal.org to get help on this plugin or more precisely go to http://jaspreetchahal.org/wordpress-scroll-to-top-plugin
<h3>Screenshots ==-</h3>
<ol>
<li>A screen shot of the options page</li>
<li>Shows a style at the bottom of the page</li>
</ol>
<h3>Donations</h3>
If you would like to donate to help support future development of this plugin, please go to <a href="http://jaspreetchahal.org/wordpress-scroll-to-top-plugin" rel="nofollow ugc">Jaspreet Chahal</a>

jcwp scroll to top

This plugin gives you granular control on styles and positioning of your 'Scroll to top' text. Many variety of easing animations supported.

LZ Scroll Bar vs jcwp scroll to top