Custom response repeater
With the web part from this article you can return your listed items from any data source web part or directly through the repeater properties in any content type you need within a custom response.
Please download this package (v8.2.25) or this package (v10.0.25) or this package (v11.0.10) and follow the steps below. Also this web part is just a proof of concept and hasn't been tested for all possible scenarios.
Import downloaded package to your Kentico 8.2.25 or newer and do not forget to check both the Import files (recommended) checkbox and then the Import code files checkbox in Step 2 of the importing process.
Once the package is imported, the Custom response repeater new web part is available.
The Custom response repeater web part can be configured same way you configure your listing web parts (Content section) or you can link it via the Data source name property:
The web part returns custom response only on your live site (in the administration you’ll see standard transformation output).