The document outlines seven essential WordPress plugins for web developers, emphasizing the importance of data backup, debugging, theme customization, security, user management, and CSS editing. Key plugins mentioned include UpdraftPlus for backup, Debug Bar for debugging, Theme Check for theme evaluation, Wordfence for security, User Switching for account management, Query Monitor for tracking performance issues, and Advanced CSS Editor for real-time styling. Each plugin is designed to enhance the efficiency and security of website management.