TuniLame

You will be able to configure the color, size, link and link’s target of each button and even add a defaut button for many posts. 
To use it, just take a look on the plugin’s configuration page which contains all the informations and settings for the default button. 
Add the button by using <code>[button color= size= link= target=]text that will be shown as button's value[/button]</code>
Attributes that can be used: 
* color: There is 7 different colors: pink, magenta, green, red, orange, blue and yellow 
* size: There is 4 different sizes: small, medium, large and super 
* link: The link of the button. Example: Your site’s URL http://mysite.com 
* target: The link’s targeted window, can be: blank, new, parent, self or top 
Exemple: <code>[button color=blue size=super link=http://twitter.com/tunilame]Follow me![/button]</code>
Simply add <code>[button]</code> in you posts when you want to use the defaut settings.

CSS3 Buttons

Add coloured CSS3 buttons on your posts using simply a shortcode.

jp2112

Based on <a href="http://www.briangardner.com/social-media-buttons/" rel="nofollow ugc">this blog post from Brian Gardner</a>, display cool CSS3 style gradient buttons on your site using shortcodes.
You can also call the plugin in your functions.php or in a plugin. Choose from several different color styles, partially inspired by social media, or create your own.
<h3>If you need help with this plugin</h3>
If this plugin breaks your site or just flat out does not work, please go to <a href="https://wordpress.org/plugins/standout-css3-buttons/#compatibility" rel="ugc">Compatibility</a> and click “Broken” after verifying your WordPress version and the version of the plugin you are using.
Then, create a thread in the <a href="https://wordpress.org/support/plugin/standout-css3-buttons" rel="ugc">Support</a> forum with a description of the issue. Make sure you are using the latest version of WordPress and the plugin before reporting issues, to be sure that the issue is with the current version and not with an older version where the issue may have already been fixed.
Please do not use the <a href="https://wordpress.org/support/view/plugin-reviews/standout-css3-buttons" rel="ugc">Reviews</a> section to report issues or request new features.
<h4>Features</h4>
<ul>
<li>Create unlimited number of modern style buttons</li>
<li>Works with most browsers, but degrades nicely in older browsers</li>
<li>CSS3 compliant, no Javascript or other code is used to generate button (note that Javascript is used to open links in new windows)</li>
<li>CSS only loads on pages with shortcode or function call</li>
<li>You can use shortcodes inside shortcodes, i.e. [standout-css3-button][my_shortcode][/standout-css3-button]</li>
<li>Many different color styles to choose from, but you can also create your own</li>
<li>Custom CSS automatically busts caches when you update it. Change it as often as you want, it will display changes in real-time!</li>
</ul>
<h4>Shortcode</h4>
To display on any post or page, use this shortcode:
[standout-css3-button href=”http://www.yahoo.com/”]Button text goes here[/standout-css3-button]
Make sure you go to the plugin settings page after installing to set options.
If you use and enjoy this plugin, please rate it and click the “Works” button below so others know that it works with the latest version of WordPress.

Standout CSS3 Buttons

Display CSS3 style buttons with gradient color styles on your website using shortcodes or PHP function call.

CSS3 Buttons vs Standout CSS3 Buttons