AddThis Social Bookmarking Widget
Help your visitor promote your site! The AddThis Social Bookmarking Widget allows any visitor to bookmark your site easily with many popular services. Sign up for an AddThis.com account to see how your visitors are sharing your content–which services they’re using for sharing, which content is shared the most, and more. It’s all free–even the pretty charts and graphs. By The AddThis Team.

Akismet
Akismet checks your comments against the Akismet web service to see if they look like spam or not. You need a WordPress.com API key to use it. You can review the spam it catches under “Comments.” To show off your Akismet stats just put <?php akismet_counter(); ?> in your template. See also: WP Stats plugin. By Matt Mullenweg.

All in One SEO Pack
Out-of-the-box SEO for your WordPress blog. By Michael Torbert.

Collapsible Archive Widget
Display Collapsible Archive in yous sidebar to save space. By Ady Romantika.

CSS Cache Buster
CSS Cache Buster does one very simple but very powerful thing: it ensures that your WordPress blog delivers the very latest version of your CSS stylesheet to your visitors, no matter how often or how rarely your edit for CSS. You no longer need to worry that you’ve made a CSS change that others won’t see because of caching issues at their end. Technically, this plugin automatically appends a last-modified date/timestamp to the end of your stylesheet url. And since this feature is applied as a filter, you don’t have to touch your theme files. It just works. Simple! By Alister Cameron // Blogologist.

Google XML Sitemaps
This plugin will generate a sitemaps.org compatible sitemap of your WordPress blog which is supported by Ask.com, Google, MSN Search and YAHOO. Configuration Page By Arne Brachhold.

Hello Dolly
This is not just a plugin, it symbolizes the hope and enthusiasm of an entire generation summed up in two words sung most famously by Louis Armstrong: Hello, Dolly. When activated you will randomly see a lyric from Hello, Dolly in the upper right of your admin screen on every page. By Matt Mullenweg.

My Custom Widgets
Define your own widgets and include them into your theme. By Janek Niefeldt.

Simple Archive Generator
A plugin which simply lists all posts by category. By Peter Sterling.

Viper’s Video Quicktags
Easily embed videos from various video websites such as YouTube, DailyMotion, and Vimeo into your posts. By Viper007Bond.

WP-Optimize
This plugin helps you to keep your database clean by removing post revisions and spams in a blaze. allows you to rename your admin name also. Additionally it allows you to run optimize command on your wordpress core tables (use with caution). By Ruhani Rabin.

WP-reCAPTCHA
Integrates reCAPTCHA anti-spam solutions with wordpress By Jorge Peña.

WP Security Scan
Perform security scan of WordPress installation. By Michael Torbert.