Steven Vachon

This plugin allows you to create internal <code><a></code> links within your content that will not break when things get renamed or moved. While there are similar plugins available, they do not offer important SEO options.
You can add any HTML attribute to your link as long as it’s prefixed with “attr_”. And because it supports attributes that may not currently exist, it is future proof.
Examples:
<ol>
<li>Link to a post/page by ID or slug
<ul>
<li>Shortcode: <code>[link id="1234"/]</code></li>
<li>Shortcode: <code>[link slug="post-slug"/]</code></li>
<li>Output: <code><a href="http://domain.com/post-slug/">Post Title</a></code></li>
</ul>
</li>
<li>Link to a category by slug
<ul>
<li>Shortcode: <code>[link cat="cat-slug"/]</code></li>
<li>Output: <code><a href="http://domain.com/cat-slug/">Category Name</a></code></li>
</ul>
</li>
<li>Link to a tag by slug
<ul>
<li>Shortcode: <code>[link tag="tag-slug"/]</code></li>
<li>Output: <code><a href="http://domain.com/tag-slug/">Tag Name</a></code></li>
</ul>
</li>
<li>Custom text instead of retrieved title
<ul>
<li>Shortcode: <code>[link id="1234"]custom text[/link]</code></li>
<li>Output: <code><a href="http://domain.com/post-slug/">custom text</a></code></li>
</ul>
</li>
<li>Additional attributes for SEO/other
<ul>
<li>Shortcode: <code>[link id="1234" attr_rel="something" attr_itemprop="specialty"/]</code></li>
<li>Output: <code><a href="http://domain.com/post-slug/" rel="something" itemprop="specialty">Post Title</a></code></li>
</ul>
</li>
</ol>

SEO Internal Link Shortcode

Internal links to posts, custom-type posts, pages, categories and tags with any HTML attribute(s).

Ramoonus

This plugin adds the Modernizr to your WordPress installation. 
Modernizr is a small JavaScript library that detects the availability of native implementations for next-generation web technologies, i.e. features that stem from the HTML5 and CSS3 specifications. Many of these features are already implemented in at least one major browser (most of them in two or more), and what Modernizr does is, very simply, tell you whether the current browser has this feature natively implemented or not.
For documentation visit http://www.modernizr.com/docs/

Modernizr for WordPress

The 2.8.4 version inserts broken javascript link. I posted a message about this in the support section for the plugin and the author has not responded or fixed the problem. Now, any site that I've added this plugin to can be broken if the user runs an update. 

Instead, if you need Modernizr, insert the following into your header.php file just after <?php wp_head(); ?>:

<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/modernizr/2.8.3/modernizr.min.js"></script>

Doesn't work - Plugin Defunct

This plugin adds the Modernizr to your WordPress installation.

SEO Internal Link Shortcode vs Modernizr for WordPress