YouTube Plus

Think those Mountain View engineers could be working harder on YouTube? YouTube Plus proves it, bringing a whole host of extra functions to the video sharing site: pop-out windows, frames-per-second control, recommendation blacklists, frame grabs, and more.

OmniSidebar

Essentially a supercharged sidebar for navigating around the web more easily, this add-on gives you the ability to position the sidebar on either side, bring up a smaller mini pane, undock the sidebar, and pack more information into the window from various sources.

AdBlock Plus

Even though web advertising pays our wages, we know some sites don’t always use ads responsibly, and AdBlock Plus puts you back in control. You can tweak your ad display settings to your heart’s content and the extension protects you against malware too.

LastPass

On today’s web, you need a password manager, and LastPass is one of the most comprehensive and intuitive out there. It integrates smartly into Firefox to securely manage all of your passwords, plus your login details and other sensitive bits of data.

Greasemonkey

Greasemonkey is the easier way into tweaking and customizing some of the biggest sites on the web, from Gmail to Facebook to YouTube, and tailoring how they look. Casual users might be put off by the need to hunt out and install scripts, but there are always plenty out there to discover.

Tab Mix Plus

If you’re constantly opening new tabs, this extension is a no-brainer. Tab Mix Plus takes your tabbing to the next level, with features like tab duplication, customizable tab clicking, tab focus settings, and a session manager that enables you to save and bring back bunches of tabs at once.

Click & Clean

Keep Firefox trim and your data safe with this add-on, which can help you wipe traces of your browsing history (from cache to cookies), put limits on the ways sites can track you, securely delete files from disk, clean up after Firefox is shut down, and more besides.

Beyond Australis

Beyond Australis is based on the current Firefox theme but brings with it a few visual tweaks that you might find aesthetically pleasing. It can minimize the amount of interface you see on screen, for example, and features a pop-up URL field, auto-hide mini bar and toolbar.

DownThemAll!

Take your downloading capabilities to the next level with this add-on. Not only can it speed up your downloads with some behind-the-scenes trickery, it lets you pause and resume downloads with ease, as well as collect all the links and images on a webpage in one go.

FireFTP

There’s no need to spend time installing and configuring a separate FTP package when FireFTP puts one right inside your browser, complete with all the basic tools you’d expect from an FTP utility. It includes some handy search, filter, and comparison options too.

Buffer

If you want to quickly share sites of interest on your social networks, then Buffer is difficult to beat. It also comes with a scheduling option, so you can space out your posts across the course of a day, and send the same links of note to Twitter and Facebook simultaneously.

All-in-One Sidebar

This is another add-on for managing your all-important sidebar. This one comes with features like quick show/hide, instant access to bookmarks, history, downloads, add-ons, and more, location and behavior options, plus support for a ton of extra customizations and tweaks.

Turn Off The Lights

Sometimes the simplest ideas are the best. Turn Off The Lights will activate a ‘cinema’ mode when you’re watching video on the web, dimming the rest of the screen to give you less eye strain and a better video-watching experience. It’s easily configurable too.

Pushbullet

We’ve recommended Pushbullet in the past, and it remains one of the best ways of getting alerts and useful info between your phone and your browser. Whether you want to send an SMS from Firefox or need to beam a picture to a friend, Pushbullet takes care of it.

Fasterfox

There are a lot of ways to tweak Firefox to make it run faster, but they require some fiddling under the hood of the browser, and you can apply all the key ones easily with the help of Fasterfox. It speeds up everything from page loading times to your downloads.

FireGestures

It’s only when you actually try mouse gestures in your browser that you realize just how useful and intuitive they can be, and FireGesture lets you set up a whole host of gestures right inside Firefox, letting you speedily navigate the web with a few flicks of your wrist.

Enhanced Middle Click

Speaking of enhanced web browsing, this one gives extra powers to your mouse’s scroll wheel. You can use it to (for example) display a menu of current tabs, close the current tab, bring up your bookmarks, run a search, and more besides.