BitRef will help you view the current balance of any Bitcoin address. Just type: "btc [space or tab] bitcoin_address" in Firefox's address bar. This is the easiest and fastest way to check balance of any Bitcoin address.
Distill Web Monitor (formerly AlertBox)
Distill runs in your browser to check monitored pages for changes. Get instant alerts as soon as a change is detected
DownThemAll is fast, reliable and easy-to-use! It lets you download all the links or images contained in a webpage and much more: you can refine your downloads by fully customizable criteria to get only what you really want! Be in full control over your downloads, dedicated speed and number of parallel connections at any time. Use Metalinks or add mirrors manually to download a file from different servers at the same time.
Displays a country flag depicting the location of the current website's server and provides a multitude of tools such as site safety checks, whois, translation, similar sites, validation, URL shortening, and more..
Automate Firefox. Record and replay repetitive tasks. If you're tired of manually visiting the same sites, filling out forms, downloading files and extracting data, then iMacros is for you! Save time, effort and money with iMacros browser automation!
Adds zoom and rotation functionality for images
Opens all images from a page into a new tabbed window. Great for image focused sites like reddit, 4chan, tumblr etc
Lightbeam is a Firefox add-on that enables you to see the first and third party sites you interact with on the Web. Using interactive visualizations, Lightbeam shows you the relationships between these third parties and the sites you visit
Extracts all links from web page, sorts them, removes duplicates, and displays them in a new tab for inspection or copy and paste into other systems
Capture the whole web page, a part of it or the whole browser window, edit your screenshots in a very user-friendly interface and save the images to Google Drive
RSS Ticker loads your Live Bookmarks and scrolls their entries across your screen while you surf
ScrapBook is a Firefox extension, which helps you to save Web pages and easily manage collections. Key features are lightness, speed, accuracy and multi-language support
Use the context menu (right click) to search on YouTube any text from other websites.
Searches the current website using search engine of your choice (DDG, Google,Yahoo,Bing)
TinEye is a reverse image search engine. The extension adds a context menu item so you can search for an image to find out where it came from, how it is being used, if modified versions of the image exist, or to find higher resolution versions
Wappalyzer is a browser extension that identifies software on websites
Search for copies of the images using Yandex.ru, Tineye.com, Google.com, Baidu.com and VK.com via right click menu
Distill runs in your browser to check monitored pages for changes. Get instant alerts as soon as a change is detected
Watch Youtube Videos, frame by frame
Discover webpages similar to the page you're currently browsing
Highlight or right-click on a section of text and click on Translate icon next to it to translate it to your language. Or, to translate the entire page you're visiting, click the translate icon on the browser toolbar
Hunch.ly *Paid
Inspector Hunchly toils in the background of your web browser to track, analyze and store web pages while you perform online investigations. Forgets nothing, keeps everything.
Lightshot is the fastest way to take a customizable screenshot. Simple interface, nothing useless and light weight
Web Scraper is a chrome browser extension built for data extraction from web pages. Using this extension you can create a plan (sitemap) how a web site should be traversed and what should be extracted. Using these sitemaps the Web Scraper will navigate the site accordingly and extract all data. Scraped data later can be exported as CSV