I would like to use the Custom List to show, filter and export User Stories and Defects at the same time. Is there a way to achieve this?
With the current Custom List App, it is not possible. You can use Work Views to show, filter and export multiple types of artifacts.
If you still want to use this on a Custom List, the Rally Community has provided custom code to enable Defects and Stories on the Same Custom list. You can find the thread here:
https://community.broadcom.com/communities/community-home/digestviewer/viewthread?MID=758346#bmec493726-f926-4b7d-ab8c-c40135a9cfb9
Because this is custom code, it is not supported by Rally. If you have questions, please post to the Community thread for assistance by the authors of the custom code.