Yes, you should be able to do that, unless you are reasonably certain that the information might be used to commit credit card fraud/identity theft.
If you think they might be used illegally, I believe there are already laws to charge you with that relate to facilitating a crime.
If you don't think they will be used illegally, then what's the harm in selling them to someone else?
Re:GDPR: Removing Monal from the EU
by jimmaswell on Thursday May 17, 2018 @08:37PM
(#17097647)
The credit card example was already illegal by other, more targeted legislation.
Nobody likes getting a lot of junk mail, but it's not the end of the world. I actually got my first credit card from a pre-approved offer found in junk mail.
Months later, I discover that I can sell my stock of credit card information on the darknet for some nice extra income.
Should I be allowed to do that? What if it weren't credit card details but just postal addresses?