Browser Calories : The easiest way to measure your performance budget.
Memex : Browser Extension to full-text search your browsing history & bookmarks.
TagUI : TagUI is a general purpose tool for automating web interactions
Browser Pong : A pong game made of browser windows. Browser Pong attempts to think with the boxes.
Accessibility Developer Tools : Accessibility audit and element properties.
This extension will add an Accessibility audit, and an Accessibility sidebar pane in the Elements tab, to ...
Measure between the following elements: images, input-fields, buttons, videos, gifs, text, icons. You can measure everything you see in the browser.