If you would still like to use Postman in a non signed in state, you can do so using the Lightweight API Client to send HTTP, WebSocket, gRPC, and GraphQL requests, to test your APIs.
In the Lightweight API Client, you have the option to Export your data from the 
> Settings > Data.
After you have created a free account, you can use the Migrate data option from the same menu mentioned above, to continue using the Collections and Environments.
Sharing some good security practices here too:
Follow safe practices with your data and credentials when using your Postman account.
- Be careful to avoid accidental data exposure when making a Postman element public, such as workspaces, collections, and environments.
- We strongly recommend you avoid storing sensitive data anywhere except within Postman environments. Storing variable values only in the
Current valuefield, will ensure that the data is never sync’d. - You should also use environment variables with a secret type to store sensitive data and credentials, including API keys and access tokens.
- Learn more by reading our shared responsibility model.