What design patterns have you used besides Page Object?

In addition to the Page Object pattern, I often use the following patterns in test automation:

• Factory — for creating page or element objects with different configurations, which simplifies test scaling.
• Singleton — for managing a single instance of the browser driver to avoid conflicts and redundant resource creation.
• Facade — for creating a simplified interface for interacting with complex subsystems, such as APIs or databases.
• Builder — for step-by-step creation of complex test data or objects.

Example of using Factory to create pages:

public class PageFactory {
    public static BasePage getPage(String pageName, WebDriver driver) {
        switch(pageName) {
            case "Login":
                return new LoginPage(driver);
            case "Dashboard":
                return new DashboardPage(driver);
            default:
                throw new IllegalArgumentException("Unknown page: " + pageName);
        }
    }
}