Barba.js [↗]
barba.js is a small (4.4kb minified and gzipped), flexible and dependency free library that helps you creating fluid and smooth transitions between your website’s pages.
It helps reducing the delay between your pages, minimizing browser HTTP requests and enhancing your user’s web experience.
I kind of like the idea of these push state transitions, but I don’t come across many websites that use them, apart from the occasional arty portfolio site.