Magento 2 Restrict Zip Code Extension - Cynoinfotech
https://www.cynoinfotech.com/product/restrict-zip-codes-magento-2-extension/
Restrict Zip Codes The Magento 2 extension allows customers to restrict orders based on invalid zip codes before they complete the purchase process. The store owner can set error messages if the customer's pin code is restricted or unavailable. Restrict Zip Codes The Magento 2 extension allows the customer to enter a zip code on the product page to check product availability.