Social Fixer for Facebook
From the FAQ
http://socialfixer.com/faq.php
Social Fixer is a personal project of the author, Matt Kruse. I am the sole programmer, designer, tester, documentation-writer, and marketer. You can view my personal site or even search Google for my name to see that I have been doing this stuff for a long time, and my reputation is solid. I build it because I love to create things, and this is my creative outlet. I've been working on it in my free time since 2009 and there are hundreds of thousands of people who use it every day.
Social Fixer has been written about on Lifehacker, ComputerWorld, InsideFacebook.com and many other places (sometimes under it's previous name, Better Facebook)
And rest assured - Social Fixer will not compromise your privacy or security, and it won't insert ads, spam, porn, or malware. There are no viruses or spyware. The code is safe.