Ahrefs SEO Toolbar Mozilla Addon On-page SEO report, broken link checker, redirect tracer, and country changer for SERP in one add-on.If you have an active account at ahrefs.com, you will also get instant access to Page, Domain, and keyword metrics via your Ahrefs account.
Colorpick Eyedropper Mozilla Addon A simple eye-dropper & color-picker tool allowing you to select color values from webpages.You will need to enable the add-on bar Firefox menu->Options->Add-on BarOR View->Toolbars->Add-on BarThen refresh the page.
CORS Everywhere Mozilla Addon A firefox addon allowing the user to enable CORS everywhere by altering http responses.Report issues to the repository, with enough information to reproduce the problem: https://github.com/spenibus/cors-everywhere-firefox-addon/issues
Flash Debugger Mozilla Addon Debug Flash/SWF/Flex files on the web. Edit properties and inspect elements on the fly. View log output inside the extension. Run AS3 code against the active SWF. Profile memory consumption and much much more...