scribu

This plugin adds a dropdown with all the plugin author names. When you select an author, only those plugins remain visible.
Links: <a href="http://scribu.net" rel="nofollow ugc">Author’s Site</a>

Filter Plugins

Allows you to quickly filter plugins by author in the admin.

Pat Hawks

dirtysuds

Will embed a PDF file using Google Docs Viewer 
Simply include the URL for a PDF document on it’s own line, or wrapped in the embed tag like <code>[embed]http://example.com/file.pdf[/embed]</code> and the plugin will embed the PDF into the page using the Google Docs Viewer embed code. 
The url must end with <code>.pdf</code>
Supported attributes in the embed tag are <code>class</code> <code>id</code> <code>title</code> <code>height</code> and <code>width</code>

Embed PDF

Adds pseudo oembed support for PDF documents

Filter Plugins vs Embed PDF