ThickBox
If you’d like to embed ThickBox into your blog just install this plugin, insert ThickBox compliant markup whereever you want and you’re all set.
WordPress Popular Posts
WordPress Popular Posts is a sidebar widget to show the most popular posts in your blog. Many options has been included in it so you can customize it to your liking.
Simple Sidebar Navigation
This plugin adds a widget into the Widgets dashboard that allows in a simple way, without writing any PHP code on your part, to create custom navigation in any sidebar pre-defined by your WP theme.
AskApache Debug Viewer
This plugin is custom-made for WordPress Developers, Plugin Developers, or anyone wanting to see under the hood of their website and diagnose problems
Lexi
Sometimes an RSS feed has a low bandwidth and during the page creation WordPress has to wait after those RSS feeds has been downloaded. This plugin allow the site to read the RSS after the page was created, not during the process.
xili-tidy-tags
This plugin offer to xili-language plugin a smart way to create sub-set of tags according language of the displayed post (or category). The tag cloud content is depending of the front current language in the multilingual website.
Submit to Any
This plugin is for bookmarking your posts into StumbleUpon, Slahdot, Technorati, Digg and Del.icio.us. You have to do nothing but just activate the plugin. It automatically add the bookmarking options just below to your posts. It also has a stylish button for subscribing to your RSS feed.
StatPress Reloaded
This plugin shows you real time statistics about your blog. It collects information about visitors, spiders, search keywords, feeds, browsers, OS etc.
Admin Links Widget
This plugin provides a widget which can contain links to pages in the administration panel in one of your sidebars. These links are only visible to those already logged in as an administrator.
WP Captcha-Free
WP Captcha-Free blocks comment spam by using a combination of time-based hash (a.k.a. Time Based Tokens, TBT) and JavaScript (AJAX). When a comment is posted the plugin validates a hash based on time (and some other parameters). Comments posted via automated means will not have a hash or will have an expired hash and will be rejected. Unlike using a captcha, this does not place any burden on the commenter.