Page Ruler: A useful tool for web developers - YouTube
Ruler Measurement
Control Alt Achieve: The Best Virtual Protractor and Ruler for Chrome
5 Ruler Extensions For Google Chrome
5 Free Ruler Extensions For Google Chrome
html - How to show full ruler lines in the Chrome inspector? - Stack Overflow
GitHub - vishalsinghdeepak/Google-Chrome-Extension-Ruler: Developed chrome extension, Ruler, that helps in measuring arbitrary shapes on the webpage and can be easily integrated into any other browser.