Scrollbar of Contents
https://chrome.google.com/webstore/detail/cfmkncejaemmcobmaabfigljmnkeecdm
Scrollbar of Contents is a Chrome extension that creates clickable markers for all the headings of a page and places them proportionately next to the scrollbar.
The markers enable you to jump between different sections of the page and help to quickly find what you are looking for. They are especially useful when navigating long webpages.