In one of our projects we lost a lot of url_key entries, due to the uninstallation of a third party SEO module. This module wil find all the products without an url key and regenerates them using the product name as a basis.
composer require vendic/magento2-regenurlkeysphp bin/magento regenerate:product:urlkeysVendic - Magento 2 develops technically challenging e-commerce websites using Magento 2. Feel free to check out our projects on our website.