Thank you for providing the free tier.
It would be even more awesome if zone transfers were allowed on the free tier (limiting to Cloudflare as the primary is fine).
Other users who agree that it would be nice: Allow Outgoing Zone Transfers
Given that the free tier is aimed at “personal or hobby projects that aren’t business-critical” I would never expect this to be available on free tiers.
You can export your DNS zone in bind format using the API, but this assumes all records are .