Various free Quicklabs posted by Satish V;
https://github.com/sathishvj/awesome-gcp-certifications
https://medium.com/@sathishvj/qwiklabs-free-codes-gcp-and-aws-e40f3855ffdb

Free Quicklabs for GCP;
Free Google Quicklabs

Data Specific GCP Quicklabs;
GCP Data Quicklabs