You can request a copy from ICANN through the Centralized Zone Data Service (CZDS). It's a pretty neat service and will give you access to zone files for a few months, you just need to file a request to one/multiple TLDs you are interested in seeing.

Sometimes larger TLDs take a bit longer to respond to requests, whereas some others automatically accept all requests.

https://www.icann.org/resources/pages/czds-2014-03-03-en https://czds.icann.org/home