sass-vary Allows you to set a flexible map of variables to run through it in a single friendly call.
Progressive Enhancement A collection of organised links where you can learn about progressive enhancement.
localFont Vanilla JS web app to build a setup to implement localStorage web font loading in seconds.
Paraxify.js A light, smooth, non-obtrusive parallax plugin in Vanilla JS implemented with a PE approach.
ext(); Sass mixin to set selector budgets, gaining control over Sass' @extend directive.
Framote A free responsive website testing tool allowing you to control the devices from the web.

I also play around in Codepen, trying to reach the limits of CSS, building optical ilussions and 3D experiments.