Plugins are ways to extend and add to the functionality that already exists in WordPress. One of the primary advantages of using the self-hosted version of WordPress from WordPress.org is the ability to upload and use plugins on your WordPress site.  Here is the list of top WordPress plugins you should be using to improve your website.

Best WordPress Plugins

WordPress Anti-spam Plugins

Akismet: Akismet checks your comments against the Akismet Web service to see if they look like spam or not.

PlusCaptcha: The easiest captcha to setup and execute, with auto-setup feature. Simple to install and use, and the most simple way to stop spam.

Anti-spam: Anti-spam plugin blocks spam in comments automatically, invisibly for users and for admins.

WP-SpamShield Anti-Spam: An extremely powerful and user friendly WordPress anti-spam plugin that stops blog comment spam cold, including trackback and pingback spam.

Antispam Bee: Another great plugin to fight spam.

WordPress SEO Plugins

All in One SEO Pack: All in One SEO Pack is a WordPress SEO plugin to automatically optimize your WordPress blog for Search Engines such as Google.

WordPress SEO by Yoast: Improve your WordPress SEO: Write better content and have a fully optimized WordPress site using Yoast’s WordPress SEO plugin.

Redirection: A WordPress plugin to manage 301 redirections and keep track of 404 errors without requiring knowledge of Apache .htaccess files.

SEO by SQUIRRLY: Squirrly SEO helps you write content that is SEO friendly and ALSO Human friendly. You’ll get to improve your rankings, while providing your readers with great content.

Google XML Sitemaps: This plugin will generate a special XML sitemap which will help search engines like Google, Bing, Yahoo and Ask.com to better index your blog. With such a sitemap, it’s much easier for the crawlers to see the complete structure of your site and retrieve it more efficiently.

SEO Smart Links: SEO Smart Links provides automatic SEO benefits for your site in addition to custom keyword lists, nofollow and much more.

Broken Link Checker: This plugin will check your posts, comments and other content for broken links and missing images, and notify you if any are found.

WordPress Caching Plugins

Hyper Cache: Hyper Cache is flexible and easy to configure cache system for WordPress specifically written for people which have their blogs on low resources hosting  provider (cpu and mysql).

W3 Total Cache: The only WordPress Performance Optimization (WPO) framework; designed to improve user experience and page speed. Web Performance Optimization (WPO) using caching: browser, page, object, database, minify and content delivery network support.

WP Super Cache: A very fast caching engine for WordPress that produces static html files. This plugin generates static html files from your dynamic WordPress blog. After a html file is generated your webserver will serve that file instead of processing the comparatively heavier and more expensive WordPress PHP scripts.

WordPress Security Plugins

Wordfence Security: Wordfence Security is a free enterprise class security and performance plugin that makes your site up to 50 times faster and more secure.

BulletProof Security: BulletProof Security protects your website against 100,000’s of different hacking attempts/attacks. The .htaccess security filters in BulletProof Security are designed to match malicious and nuisance attack patterns.

iThemes Security: iThemes Security (formerly Better WP Security) gives you over 30+ ways to secure and protect your WordPress site.

WordPress Gallery Plugins

WP Gallery Bank: WP Gallery Bank is an enhanced tool to create Responsive and Beautiful Galleries for WordPress Websites.

NextGEN Gallery: NextGEN Gallery is the most popular WordPress gallery plugin, with the ability to batch upload, import meta data, add/delete/rearrange/sort images, edit thumbnails, group galleries into albums, and more.

Grand Flagallery: Grand Flagallery is a powerfull media and image gallery plugin. Easy interface for handling photos, image galleries, audio and video galleries. You can easy upload images, create music and video playlists, create photo gallery, group pictures in photo slideshow and add descriptions for each image, mp3 or video.

WordPress Backup Plugins

UpdraftPlus Backup and Restoration: Backup and restoration made easy. Complete backups; manual or scheduled (backup to S3, Dropbox, Google Drive, Rackspace, FTP, SFTP, email + others).

BackWPup Free: BackWPup Free is the number 1 backup-plugin for WordPress with nearly 1.000.000 downloads and in the top 20 of all WordPress Plugins.

BackUpWordPress: BackUpWordPress will back up your entire site including your database  and all your files on a schedule that suits you.

WordPress Membership Plugins

s2Member: s2Member is a powerful membership plugin for WordPress. Protect members only content with roles/capabilities.

WP-Members: WP-Members is a free membership management framework for WordPress that restricts content to registered users.

WordPress Calendar Plugins

The Events Calendar: Create and manage events with ease. Get professional-level quality and features backed by a team you can trust.

All-in-One Event Calendar: The All-in-One Event Calendar is a beautiful way to list your events in WordPress and easily share them with the rest of the world. The plugin has a clean visual design with a powerful set of features to create the most advanced calendar system available for WordPress.

My Calendar: Show events from multiple calendars on pages, in posts, or in widgets. The plugin supports individual event calendars within WordPress Multisite, multiple calendars displayed by categories, locations or author, or simple lists of upcoming events.

WordPress Mobile Plugins

WPtouch Mobile Plugin: WPtouch is a mobile plugin for WordPress that automatically enables a simple and elegant mobile theme for mobile visitors of your WordPress website.

Any Mobile Theme Switcher: Detects all the Mobile Browsers and loads the mobile theme as per your settings done in admin.

WordPress Newsletter Plugins

MailPoet Newsletters: Send newsletters, post notifications or autoresponders from WordPress easily, and beautifully.

SendPress: SendPress is a plugin for WordPress that allows to write and send newsletters, and to gather and manage the subscribers.

WordPress Social Media Sharing Plugins

AddThis: AddThis provides the best sharing, social, recommended content, and conversion tools to help you make your website smarter.

ShareThis: The ShareThis plugin offers a lot of great features such as analytics, mobile support and the ability to track what visitors are copying and sharing.

Shareaholic: The easiest, most effective way to grow your website traffic, effectively engage your audience, monetize, and gain insights for free.