The Multiple Sites User Sync WordPress API plugin can automatically synchronize a user from one WordPress site (blog) to other WordPress sites (blogs) when a user is added / updated / registered. Also, sync bulk users across multiple sites.
Demo: https://codecanyon.net/item/wordpress-api-multiple-sites-user-sync/21608092
Content Egg has many pro features which you can find on top comparison sites. Creating such sites is possible now for everyone without spending thousands of dollars for developers and content makers.
Demo: https://codecanyon.net/item/content-egg-all-in-one-plugin-for-affiliate-comparison-deal-sites/19195707
Akeeba Backup Pro is the most widely used open-source backup component for the Joomla! CMS.
Demo: https://www.akeeba.com/subscribe/akeebapro.html
JS Restora is a deliciously designed Joomla restaurant template built for all types of restaurants and food-related businesses to launch a website quickly.
Demo: https://www.joomshaper.com/joomla-templates/restora
WordPress API Posts and Pages Sync plugin can sync automatically posts and pages from one WordPress site to the other WordPress sites when posts and pages add / update.
Demo: https://codecanyon.net/item/wordpress-api-posts-and-pages-sync-with-multiple-wordpress-sites/22075096