You are trying to export or track which subscriptions have been gifted.
- WooCommerce Subscriptions
- Gifting for WooCommerce Subscriptions
- WooCommerce Subscriptions Importer and Exporter
This will add a new ‘Recipient’ column to your CSV Export, which will include the user ID of the recipient. After importing into Google Sheets or similar, you can sort by that colum to determine the subscriptions which have a recipient, i.e. which ones have been gifted.