Arjun Sharda - Founder & Mantainer, wrote most of the CSS & JS, and some HTML
Julien Van Beveren (https://github.com/julienvanbeveren) - Early contributor and former collaborator, helped with formatting and some JS
W3Schools (https://w3schools.org) - Was a reference when needed for HTML
And there are way, way more. These are just 3 mentions.