In Netsuite's REST web services help documentation, there's a reference to a Postman collection: https://netsuite.custhelp.com/app/answers/detail/a_id/86958/kw/postman
You can download the REST web services Postman environment template and collection of sample requests from the SuiteTalk tools download page at https://[accountID].app.netsuite.com/app/external/integration/integrationDownloadPage.nl. To access the page, you must substitute your account ID in the URL.
Note To access the Postman environment template and collection, the REST Web Services feature must be enabled, and you must have the REST web services permission assigned to your role. For more information, see REST Web Services Prerequisites and Setup.
However, when I go to the download page (with the correct account ID and REST web services permission), there's only a download available for "NetSuiteDataLoader.zip", which does not contain the postman collection.