Which Power BI feature allows for custom visualizations?

The Power BI Visuals Marketplace is the correct choice as it serves as a central hub where users can find and download custom visualizations created by developers from the community or third-party vendors. This feature expands the range of visualization options available beyond the standard visuals that come pre-loaded with Power BI, allowing users to tailor their reports and dashboards to better meet specific analytical needs or to present data in more innovative ways.

By using custom visuals from the Marketplace, users can enhance their reports with unique designs and functionalities that might not otherwise be available, thereby improving data storytelling and insight presentation. This flexibility is essential for businesses looking to convey intricate data narratives or satisfy niche reporting requirements.

Other options such as data insights, Power Query Editor, and Report Builder do serve important roles within Power BI, but they do not specifically provide access to a marketplace for custom visualizations. Data insights focus on analyzing and highlighting patterns in data, Power Query Editor is designed for data transformation and preparation, and Report Builder is used for traditional report generation rather than custom visual development. Thus, the Marketplace distinctly fulfills the need for custom visualization capabilities.