FoxySEO is a nice FireFox addon that installs an additional toolbar allowing to instantly access multiple SEO resources and perform a plenty of SEO tasks.
Foxy SEO Tool is a free, open source toolbar that provides quick and easy access to a multitude of search engine functions such as Google Site, Yahoo! Site Explorer, Live Fromlinks, etc
Here’s a quick overview of available options:
Google menu includes:
• Google cache;
• Google site: search;
• Google search engines (Google news, Google images);
• Google Webmaster Tools dashboard etc

Yahoo! menu:
• Yahoo! SiteExplorer page for the current domain;
• Yahoo! SiteExplorer page for the current page.
"Others" menu includes Bing and its very helpful [LinkFromDomain:] operator for the current domain:

"Traffic" menu offers to quickly check traffic stats for the current domain via Alexa, Compete, Google Trends and Quantcast.
"Social media" menu gives a quick access to most popular social bookmarking and voting sites:

"Network" menu lets you check the current domain IP, geo location and server headers.
"Keyword" menu offers to search one of the following tools for a selected text:
• Dictionaries;
• Google Trends;
• Google Insights;
• Wordtracker; etc

The "tools" menu currently offers a W3C validation and Spider Simulator function which displays a web page just as a search engine would read it, in the order of the html code of the page, without the layout code.

The tool was reviewed under SEJ policy.

