Quick, single-file samples like this HTTP Request example are ideal for learning basic syntax.
You can generate samples directly within the tool. Go to File > Templates... to choose from built-in scenarios like "Recording," "JDBC Load Test," or "Web Test Plan." Core Components of a JMX File download sample jmx file
If you are looking to , several reputable repositories provide templates for various testing scenarios: GitHub Repositories: Quick, single-file samples like this HTTP Request example