Can we import any specific set of fields from any external salesforce org?

Yes, BOFC has a capability to import fields (all fields or any specific set of fields) from any external non-linked org

Experience it for yourself

Bulk Object Field Creator (BOFC) is a must-have tool, designed specifically for Administrators, that simplifies many of the tedious tasks of managing a complex Salesforce environment.

This tool is available on Appexchange and Click on below button to install the
latest version of BOFC

or learn more