ThemeShock

This lightweight plugin creates a form that is placed by default at the left of the 
content, and is fixed to the top of the page once it gets to it.
Floatin Comments serves as an alternative form to post comments that is very handy 
compared to the traditional comments form. Given that it follows you as you scroll down by 
the page, you can post a comment being at the bottom of the page but also at the 
top.
This plugin is available in 5 different languages, English, Spanish, Portuguese, 
French and Dutch, it will recognize your WordPress installation language and if 
yours is in one of the previews languages you’ll have it automatically 
translated.
<a href='http://www.wpthemeshock.com/' rel="nofollow ugc">By WpThemeShock</a> and <a href='http://www.wpthemegenerator.com/' rel="nofollow ugc"> WpThemeGenerator</a>, <a href='http://www.designshock.com/psd-text-styles/' rel="nofollow ugc">see it in action.</a>
<h3>Features</h3>
<ol>
<li>4 Different Colors</li>
<li>Fixed position when the form gets to the top</li>
<li>Ajax-Powered</li>
<li>Get 100 free sample WordPress Themes</li>
<li>5 Different languages, English, Spanish, Portuguese, French and Dutch.</li>
</ol>

Floating Comments Form Fixed Scroll Position

Floating Comments allows users to post comments to your blog through a fancy form that fallows them as they scroll down.

Digital2

supercica

Click to Call Button plugin you can use to add small floating button for your website visitors to click and call. 
This will make your user experience much better and it will make more people contact your business with ease. 
It allows you to setup position, choose phone icon, choose the color of the text and the icon and much more. 
It is very light and easy to setup and use.
<h4>FEATURES</h4>
<ul>
<li>Enter the phone number for link in a form a text without dashes or space, example: +3819166123456</li>
<li>Enter the visible part of phone number, example 066 123 456 or visible text, ex : Call us now</li>
<li>Choose button color and choose text and icon color </li>
<li>Choose from 7 added icons</li>
<li>Choose button type: square, square rounded and circle</li>
<li>Setup bottom right position of the button</li>
<li>Allows you to choose if you what to hide button from desktop users</li>
</ul>

Click to Call Button

Small floating click to call phone button for your website

Floating Comments Form Fixed Scroll Position vs Click to Call Button