As an AI language model, I don’t have real-time access to property listings or specific information on plots in Pocket 5A, Sector 18, Yamuna Expressway. To find 300 sqm plots in that particular area, I recommend following these steps:

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 5A, 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 your requirements, including plot size.
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 match your criteria.
4. Local Newspapers and Classifieds: Browse local newspapers or classified ads in the area. Sometimes, sellers advertise plots for sale directly, and you may find suitable options there.

Remember to conduct due diligence, visit the site in person if possible, and consult with professionals before making any property purchases.