1. PfpManage your passwords easily and securely, via browser extension for Firefox, Chrome, Opera
2. SearchlinkfixBrowser extension that prevents Google and Yandex search pages from modifying search result links when you click them. This is useful when copying links but it also helps privacy by preventing the search engines from recording your clicks.
3. jsdeobfuscatorDEPRECATED: Firefox extension that shows you what JavaScript code runs on a web page, even if it is obfuscated and generated on the fly. Simply open JavaScript Deobfuscator from the Web Developer menu and watch the scripts being compiled/executed.