I apologize for any confusion, but as an AI language model, I don’t have real-time access to property listings. However, I can provide some general guidance on finding 300 sqm plots in Pocket J, Sector 18, Yamuna Expressway. Here are a few steps you can take:

1. Contact Local Real Estate Agents: Reach out to real estate agents who specialize in the Yamuna Expressway area. They will have the most up-to-date information on available plots in Pocket J, Sector 18.
2. Explore Property Websites: Visit property websites that focus on the Yamuna Expressway region. These platforms often list various plots and provide filters to narrow down your search based on plot size and other criteria.
3. Consult Real Estate Developers: Check the official websites or contact real estate developers who have ongoing projects in Sector 18. They may have 300 sqm plots available or can provide information about upcoming projects that meet your requirements.
4. Local Newspapers and Classifieds: Browse through local newspapers or classified ads in the area. Sometimes, individual sellers advertise plots for sale directly, and you might find suitable options there.

Remember to conduct due diligence, visit the site in person if possible, and seek advice from professionals before making any property-related decisions.