Extensions
SaveFrom.net helper
Download YouTube, RapidShare, VK.com and 40+ sites in one click.
YouTube AdsFree
Removes popup ads on YouTube videos.
LastPass
LastPass is a free password manager and form filler. LastPass is also available for Firefox, Internet Explorer, Google Chrome and Safari.
AdBlock
Blocks ads on all websites.
Radio.corbina.ru
Listen your favorite Internet radio station!
cleanPages
improve the readability of web articles by removing clutter
Turn Off the Lights
The entire page will be fading to dark, so you can watch the video as if you were in the cinema.
YouWatch
Manage your watched videos on YouTube. Browse them, mark/hide them in a search or at pages, show them in Speed Dial. Guests can now subscribe channels.
GitHub Notifier
Displays your GitHub notifications unread count
Translator
Translate selected or entered text
Gmelius™, No Ads and Better UI for Gmail
Gmelius customizes Gmail's interface to your liking and strips away the ads. Featured on TechCrunch, Lifehacker and other high-profile technology sites.
Amazon Bestsellers and Deals
Keep an eye on the current deals from your local Amazon store.
Web Timer
Keep track of how you spend or waste your time on the Web.
Weather Forecast
Shows weather information (current conditions and forecast) for your favorite locations around the world. The weather data includes temperatures, wind, pressure, humidity, visibility and sunset/sunrise times
Documents
Viewer for online documents (e.g. PDF, MS Word)
Opera Theme Creator
Select an image, from either the web or your computer, and create your own Opera theme with it. Then try out the theme, or download it as a zip file.
AutoComplete
Provides the Autocomplete for the text input box.
VKontakte.ru Downloader
Download music/video from VK.com/vkontakte.ru
Adblock Plus
Blocks all annoying ads on the web: video ads on YouTube, Facebook ads, banners and much more.
Tab Vault
Store tabs for later without wasting space or memory.
ImagePreviewer
Shows a popup with an image preview when hovering over link.
Reddit Enhancement Suite
RES provides several addons to enhance your browsing experience - each of which is configurable. You can enable/disable any of the modules, and most of them have their own options that can also be personalized.
gCalToday
Shows todays Google calendar events.
Wikipedia+ Language Bubble
Places your preferred languages at the top of the languages list at wikimedia projects
Google maps full screen
Adds a button to make Google Maps full screen, also takes screenshots of the map.
Source
Source code related features.
Shopping Assistant
Help you compare with Amazon, eBay, .etc, when you search products on many sites
MakeLinks
Turns text web addresses into clickable links
Go to IMDb
Get IMDb rating or open movie page for highlighted text
Groupon
Groupon - Local Deals, Goods and Getaways