https://blog.cloudflare.com/incident-report-on-memory-leak-caused-by-cloudflare-parser-bug/

https://github.com/pirate/sites-using-cloudflare

This is another list
Uber
Reddit
Yelp
Digital Ocean
OKCupid
RapGenius
Coinbase
Product Hunt
Udemy
Crunchyroll
FitBit
Hacker News
Zendesk
Discord
Github pages
Chocolatey

Apparently the list keeps getting updated