Drupal offers a wide range of modules to enhance the search engine optimization (SEO) capabilities of your website. Here is an extensive list of Drupal SEO modules that were available up to my knowledge cutoff date in September 2021. Please note that the availability and popularity of modules may change over time, so it's a good practice to check for the latest updates and alternatives:

1. Pathauto: Automatically generates search-engine-friendly URLs for your content.
2. Metatag: Provides extensive control over meta tags (title, description, keywords, etc.) for each content type.
3. Google Analytics: Integrates with Google Analytics to track your website's performance.
4. XML sitemap: Helps in generating XML sitemaps for your site, making it easier for search engines to crawl your content.
5. Redirect: Manage redirects for changed URLs to prevent broken links and maintain SEO rankings.
6. SEO Checklist: A tool that provides a checklist for optimizing your site for search engines.
7. Global Redirect: Ensures that there's only one URL for each piece of content.
8. Google Analytics Reports: Provides reports and visualizations for Google Analytics data within Drupal.
9. Linkit: Makes it easier to link to other content on your site, which can improve internal linking and SEO.
10. Content Optimizer: Analyzes the content on your pages and provides recommendations for SEO improvements.
11. Real-time SEO for Drupal: Provides real-time on-page SEO analysis and recommendations.
12. SEO Compliance Checker: Checks your content for SEO best practices.
13. Yoast SEO (Drupal 7 only): An integration of the popular WordPress SEO tool into Drupal 7.
14. Path Redirect Import: Helps with importing redirects from CSV files.
15. Link Checker: Scans your site for broken or dead links, which can negatively impact SEO.
16. SEO Tools: A suite of tools for optimizing and analyzing your site's SEO.
17. Sitemap: A basic sitemap generation module.
18. Simple XML Sitemap: An alternative to the XML sitemap module, with a simpler interface.
19. SEO UI: Adds an SEO tab to node edit forms to control meta tags.
20. Canonical URL: Manages canonical URLs to prevent duplicate content issues.
21. Facebook Instant Articles: Integrates with Facebook Instant Articles for optimized content sharing.
22. Twitter Cards Meta: Provides meta tags for Twitter Cards.
23. Rich Snippets: Adds structured data to your content to improve how it appears in search results.
24. Schema.org Metatag: Adds structured data in the form of Schema.org markup to your content.
25. AMP: Implements Google's Accelerated Mobile Pages for faster mobile load times and better SEO.
26. Open Graph Meta Tags: Manages Open Graph meta tags for improved social media sharing.
27. Hreflang: Helps manage hreflang tags for multilingual and international SEO.
28. Google Custom Search Engine: Integrates Google Custom Search for improved search results.
29. SEOMoz: Integrates with SEOMoz to provide SEO analytics and insights.

Please check the availability and compatibility of these modules with your specific Drupal version, as well as any newer SEO modules that may have emerged since my last update. Additionally, always refer to the module documentation for best practices and guidelines on SEO implementation in Drupal.