DV360 API - list "Youtube & Partners" line items?

Solution 1:

Official response from their support:

Management of YouTube & Partners resources, including creation, retrieval and updating, is currently not available through the DV360 API.

If you are looking to retrieve YouTube & Partner resources, that can be done by generating and downloading SDFs using the API.

So if you just need to retrieve them you could try the second method. But you won't be able to modify them programmatically through the API.