I update this page to have the top Magento 2 modules for performance, development, ux and more.
Check the store performance tips in an admin panel dashboard
https://github.com/magehost/performance-dashboard
Defer Javascripts
https://magefan.com/rocket-javascript-deferred-javascript
Access a terminal using the Magento 2 admin panel
https://packagist.org/packages/magefan/module-cli
Check modules conflicts
https://packagist.org/packages/magefan/module-conflict-detector
Developer toolbars
https://github.com/Smile-SA/magento2-module-debug-toolbar