Possible GDPR issues with Sitecore Email Experience Manager and how to solve them.
Some tips on how to avoid problems with GDPR in Sitecore Forms and WFFM module
Practical approach to GDPR in Sitecore. How to implement right to be forgotten, right to be informed and data portability in different versions of Sitecore. Including 8, 8.2 update 7 and Sitecore 9.