jsDelivr's answer
jsDelivr is the only free CDN that aims to be production ready even for the most critical workloads. It has multiple failover systems for all of its components to ensure 100% uptime and uses multiple CDNs and datacenters for better performance.
cdnjs - An open source community driven JS/CSS CDN.
RawGit - RawGit serves raw files directly from GitHub with proper content-type headers.
CloudFlare - Cloudflare is a global network designed to make everything you connect to the Internet secure, private, fast, and reliable.
raw.githack.com - raw.githack.com serves raw files from github.com with proper Content-Type headers (like rawgit.
KeyCDN - KeyCDN is a high-performance Content Delivery Network (CDN). Lowest price globally at $0.04/GB with HTTP/2 Support and free Origin Shield.
Statically - The free optimization & CDN for images, CSS, JavaScript, and open source.