Is there a batch-download or download-all option somewhere?
As far as I’m aware, there’s not. My understanding of this is that it is on purpose. If every time there was a bundle with a lot of items, and a big percentage of users would batch-download the entire bundle, this would create a huge performance demand on the servers.
Downloading each of them individually would be more than a little tedious and time consuming.
Instead of downloading everything and looking at them one at a time, I would suggest that you download each item as you are about to use it.
Hope that makes sense :)