1)Admin Collapse Subpages: jQuery-powered plugin that allows expansion/collapse of subpages within pages admin (/edit.php?post_type=page) menu.

2)WP-SpamCaptcher: Integrates SpamCaptcher anti-spam methods with WordPress including comment and registration spam protection. WPMU Compatible.

3)Authorize by IP: Authorize by IP is a tool that allows access to the wordpress website based on specified IP addresses.

4)Style Replacement: Change the style of your posts with options drop down menu. You can also implement a blog-azine with a different style in every post.

5)Real Sticky: Import a Sticky page to top of site.

For Reference : http://wordpress.org