Luc André

By default, WordPress adds a base prefix to taxonomy URLs — <code>/category/</code>, <code>/tag/</code>, or any custom taxonomy base. This plugin removes those prefixes and replaces them with breadcrumb-style paths built directly from the term hierarchy, giving clean, readable URLs that reflect the content structure:
<pre><code>/parent-term/child-term/post-slug/
</code></pre>
For custom post types associated with a taxonomy, the full term path is used as the permalink base. For non-hierarchical taxonomies, only the term slug is used.
It supports:
<ul>
<li>Hierarchical and non-hierarchical taxonomies</li>
<li>Custom post type permalinks built from associated taxonomy term paths</li>
<li>Automatic detection of public taxonomies (including <code>category</code> and <code>post_tag</code>) and CPTs</li>
<li>Configuration via filter for fine-grained control</li>
</ul>
The plugin works at the permalink and rewrite layer and does not modify stored slugs or post content.

Libre Breadcrumb Permalinks

Removes taxonomy base prefixes and builds breadcrumb-style permalinks from term hierarchies.

Nitin Yawalkar

RDFa Breadcrumb provide links back to each previous page the user navigated through to get to the current page or – in hierarchical site structures – the parent pages of the current one.
It gives you a new template tag called <code>rdfa_breadcrumb()</code> that you can place anywhere in your template files. It has inbuilt RDFa content markup, so this will help Google to recognize and display the breadcrumbs on search results as well.
Check out the screenshots.

RDFa Breadcrumb

An easy template tag for showing a breadcrumb menu on your site and on google search results with built in RDFa Markup.

Libre Breadcrumb Permalinks vs RDFa Breadcrumb