SpaceHey uses some great open-source tools and libraries. Here are the Details:
necolas / normalize.css
Social Media Icons by Icondock
A free social-media icon set.
Link: https://icondock.com/free/vector-social-media-icons (archive.org version)
License: Icondock license (archive.org version)
spatie / image-optimizer
lincanbin / White-HTML-Filter
A special thanks goes to Nodehost, which were incredibly kind to help with the development of the SpaceHey Captcha!