Matheus Eduardo

This plugin adds a new field (metadata) in the section editing links in order to add social networking links (like <a href="http://twitter.com/" rel="nofollow ugc">twitter</a>, <a href="http://flickr.com/" rel="nofollow ugc">flickr</a>, etc.) to any link.
PT-BR 
Este plugin acrescenta um novo campo (metadados) na seção de edição de links para poder adicionars links de redes sociais (como <a href="http://twitter.com/" rel="nofollow ugc">twitter</a>, <a href="http://flickr.com/" rel="nofollow ugc">flickr</a>, etc) a um link qualquer.

Simply Social Links

This plugin adds a new field (metadata) in the section editing links in order to add social networking links (like twitter, flickr, etc.) to any link.

WPManiax

This plugin ads Metro style social share widget to your sidebar.
5 most popular social networks supported.
Metro Share Widget is super easy to install and configure.
More <a href="http://www.wpmaniax.com/metro-share-widget/" rel="nofollow ugc">screenshots and live sample</a> you can see on plugins’ home page
Main Features:
<ul>
<li>Easy to install and configure</li>
<li>Most popular social networks supported (Facebook, Twitter, Google Plus, LinkedIn, Reddit )</li>
<li>Fully responsive</li>
<li>Configure where to show (posts, pages, home)</li>
<li>Metro style elegant design</li>
</ul>
<h3>Feedback</h3>
http://www.wpmaniax.com/metro-share-widget/

Metro Share Widget

Add Metro style social share widget to your sidebar. 5 most popular social networks supported

Simply Social Links vs Metro Share Widget