Magento 2 Few important Tools

• Magento 2 Data Migration – https://github.com/magento/data-migration-tool
• Magento2 Coding Standards – https://github.com/magento/magento-coding-standard
• Magento 2 Front-End debugging/Inspection tools – https://github.com/magento/m2-devtools
• Magento 2 PhpStorm Plugin – https://github.com/magento/magento2-phpstorm-plugin
• Magento 2 Martketplace tool  – https://github.com/magento/marketplace-tools
• Magento 2 Performance Toolkit – https://github.com/magento/magento2/tree/2.3/setup/performance-toolkit

Reference : https://devdocs.magento.com/