On the SitePoint WordPress blog they've made an official list of the most popular plugins for 2014 according to WordPress.org's own "Most Popular" list. They provide links to the plugins, descriptions of what they do and the current number of downloads (at the time of the post).

You might have noticed that WordPress.org lists the most popular plugins in the right sidebar in the plugins directory. As we’re nearing the end of 2014, I thought it would be interesting to not only provide a quick explanation of each of these plugins, but to also explore some of the other popular alternatives. Just because a plugin is listed in the most popular list, doesn’t always mean it’s the best fit for your project. [...] It’s not a definitive list, only based on my experiences. Hopefully you’ll come across a few new plugins that you might not yet have heard of!

Plugins in their list include both some familiar names and some newcomers to the top of the pack:

• Akismet
• Contact Form 7
• Jetpack
• WordFence
• WooCommerce

As mentioned, each comes with a brief description of what they do, a link to their page on the plugin site as well as links to a few other alternatives if it's not the perfect fit.