pageload is a small and dependency-free loading indicator library to create a Youtube-like loading bar on the top of the webpage.
lazysizes is an easy yet robust JS library used to delay the loading of images (iframes, scripts, etc) until they come into view.
The preload-it library preloads & prefetches assets (e.g. videos, audios, etc) using XMLHttpRequest to optimize the loading speed of your webpage.
SpinBolt is a collection of 16 minimal, clean, circular, animated loading spinners implemented in single element and CSS/CSS3.