What are some useful Extensions you've found for your web browser?

Adblock. Is there any better?! It's so useful.

 

Hack This Page. It takes Inspect Element to a whole nother universe.

Edit: You need Chrome to use it. ^.^

 

I only have 2 add-ons installed on Firefox, cuz I don't really need any more than those 2.
#1 is Adblock, of course. Everyone's reasons for using Adblock are the same, so I won't state the obvious.
#2 would be colorPicker. It's a fast and easy to use add-on that allows you to get the hex or RGB color from any element on the page. This one is especially useful to me when coding, for obvious reasons as well.
Firefox has a built-in color picker that does the same thing as the add-on I have installed, and it's actually a lot more accurate too (due to the fact that it zoomed in and whatnot), but for some reason, I continue to use the add-on instead of the built-in tool. I guess the only thing the add-on does better is that it allows you to grab the RGB version of the color you want instead of the hex color, so that's cool.

 

Probably not the exact same one but you can find a whole bunch of them on the Chrome store for sure. It's a pretty basic thing, and I know there's dozens of 'em out there, so you shouldn't have a problem finding a good one.

 

Adblock, tumblr savior (you really need this if you use tumblr, trust me, people are nasty), stylish and new xkit (Another tumblr thing)

 

As an RPer and maker of pretty coded stuff for forums (like signatures and topic layouts and what have you), Lazarus is a lifesaver and Firebug (and Chrome's own counterpart) is a pal. Lazarus can bring back text if you accidentally lose it/changed a lot and want to go back to an earlier version. Firebug, of course, allows me to look at and modify a site's source code, which is especially helpful for figuring out image dimensions (without opening the image separately), how people coded something a certain way, how something of mine will look on a site, etc.

Adblock is also pretty useful–especially on Firefox. (Safari's sucked, orz) I also used to love LJLogin since it allowed me to switch RP accounts on LiveJournal and Dreamwidth in a heartbeat, but it doesn't seem to work with the newest version of Firefox :c

 

Adblock, of course, and the DeviantArt extension that allows me to see how many notifications I have at any time (even though I'm not really active on DA anymore). Other than that, I have the Bulbapedia extension to allow myself to quickly search info on all kinds of Pokémon (the 6th generation doesn't seem to work though, and you can only search Pokémon names, other names don't work).

Note: I use Chrome.

 

uBlock Origin may count as one for me, because I don't need to bother with some ads that are hindering my experience in the internet. Besides of this, I also used Classic Theme Restorer for Firefox, 'cos I want my browser to look unique and not looking similar to Chrome, especially when I used both browsers at the same time.