Custom Scroll Progress Indicator Bar – uScroll
uScroll is a lightweight JavaScript plugin that tracks the scroll events and auto updates the indicator bar depending on the current scroll position.
JavaScript & CSS scroll position
Minimal Horizontal Scroll Progress Bar With Pure JavaScript – skunkScroll
skunkScroll is a JavaScript library to create a responsive horizontal scrollbar which can be used to keep track of the scroll progress when scrolling down the webpage.
Pure CSS Scroll Depth Indicator
A pure CSS solution to create a fixed header progress bar indicating how far you have scrolled. Powered by @supports CSS at-rule.
Minimal Page Scroll Position Indicator – youAreHere.js
youAreHere.js is a very small (~1kb minified) JavaScript library for generating an auto-update progress bar that indicates where are you when you scroll down or up the web page.