Form to Sendinblue add-on for Google Forms integrates with Sendinblue, allowing you to create or update subscribers/contacts/members while your form is submitted.

Free Features/Limitations:
 * Create 25 contacts/month

Premium Features:
 * Create any number of contacts as per your Sendinblue plan

Video help: https://youtu.be/EgfFzlTNAwc
For more details about quotas visit: https://developers.google.com/apps-script/guides/services/quotas