pdalex

This plugin creates a glossary for your WordPress powered site. 
It will create an additional section in the admin panel, where you can add new terms to your glossary
A few notes about the sections above:
<ul>
<li>“Browse glossary” here you will see all terms.</li>
<li>“Add term” here you will add new term.</li>
</ul>

PdAlex Glossary

This plugin creates a glossary for your WordPress powered site.

MrXHellboy

This WordPress plugin (widget) will be shown when visitors are viewing a single post, category page or both. Otherwise, it wont be there at all. 
The widget contains a list of post titles from the same category(s) the visitor is viewing the post from, so the visitor is able to swiftly change posts by clicking on the titles shown. 
Posts published in multiple categories are taken care of just fine. I’ve introduced a new feature in version 1.6 which gives you the possibility to show all the categories the post has been published in or the category where the visitor has been spotted the last time(uses cookie).
The widget can be controlled with the following widget options:
<ul>
<li>Title (before the category name(s))</li>
<li>Exclude category(s) by ID</li>
<li>Exclude categories on: Single, Category, Both, None</li>
<li>Sticky posts on top: Yes | No</li>
<li>Show posts from year: a specific year or all years</li>
<li>Show widget on: categories | single posts | both</li>
<li>Show category title(s): Yes | No</li>
<li>Post has multiple categories – what now: Show all categories | Show the last category viewed</li>
<li>Show how many posts</li>
<li>Single posts view – Order: DESC | ASC</li>
<li>Single post view – Orderby: Author | Category | Date | ID | Random</li>
<li>Category view – Order:?DESC | ASC</li>
<li>Category view – Orderby: Author | Category | Date | ID | Random</li>
<li>Remove/Keep child categories</li>
</ul>
<h3>Development Blog</h3>
<a href="http://online-source.net/category/scripts/wordpress-plugins/" title="Online-Source WordPress plugins" rel="nofollow ugc">Online-Source WordPress plugins</a> 
<a href="http://online-source.net/forums/forum/support/wordpress-plugins/" title="Support forum" rel="nofollow ugc">Support forum</a>

Category Content

This Wordpress plugin (widget) will be shown when visitors are viewing a single post, category page or both. Otherwise, it wont be there at all.

PdAlex Glossary vs Category Content