This is a brilliant idea, if it doesn't exist already I hope someone puts one online, a simple wordpress page using a twentysixteen or twentyfifteen would suffice.

Or even a github page with just a list.

[UPDATE] I took the liberty to get the ball rolling.

https://github.com/killed-by-gdpr/killed-by-gdpr.github.io and

https://killed-by-gdpr.github.io/

Contributions welcome.