This is the Slack loader, single element using only CSS. An idea proposed by Fabrice :)
Modern Google spinning loader animating through four colors.
A css loader based on a gif (http://imgur.com/iWGr9AP). Try changing the $blockSize, and if you're using Firefox, uncomment the vmin variable for viewport based sizing!
Circular version of my previous loader:
WIP of 12 loader. Pure CSS.
Less CSS3 Loaders
Animated loader when redirecting a user to another page
A nice little loader with some icons.
8 CSS loaders
A minimal loader with rotating square
Need to know how to enable it? Go here.