Here are the top 10 free online resources to help you prepare for the Writing section of the TOEFL exam:

1. TOEFL iBT Writing Practice (ETS)
   Access free practice sets and example essays from the official TOEFL website, including tasks for both the Integrated and Independent Writing sections.
2. Magoosh TOEFL Blog
   Offers detailed guides, tips, and sample essays to help you master the Writing section, along with explanations of scoring criteria.
3. TestDEN TOEFL Writing Practice
   Provides free TOEFL Writing prompts and examples, as well as strategies for improving grammar, vocabulary, and coherence.
4. Good Luck TOEFL
   Features a comprehensive guide to the TOEFL Writing section, including sample essay templates and tips for structuring your responses.
5. EnglishClub TOEFL Writing Resources
   Includes sample writing tasks, essay formats, and advice for improving grammar, coherence, and organization.
6. Write & Improve by Cambridge English
   Allows you to practice essay writing and receive instant feedback on grammar, spelling, and style. Although not TOEFL-specific, it’s excellent for improving general writing skills.
7. Kaplan Test Prep
   Offers free TOEFL Writing tips, sample essays, and downloadable practice materials.
8. IELTS Liz: Writing Tips
   While designed for IELTS, many of the writing techniques and essay structures are also applicable to TOEFL.
9. TOEFL Resources Blog
   Provides free templates, scoring guides, and practice prompts specifically tailored to the TOEFL Writing section.
10. Academic Phrasebank
    A resource for learning academic phrases and structures that can elevate your TOEFL Writing responses.

Using these resources to practice essay organization, grammar, and coherence will help you excel in the Writing section of the TOEFL exam.