To get extended views in XCode?
You can't extend the downloads pane per say, but you can download more tools from the same location by going to Xcode → Open Developer Tool → More Developer Tools….

Upon logging in with your Developer ID, you can see the full list of tools, including the Command Line Tools.

I would list them here, but they're behind the developer login so can't be posted publicly.



There are even more Developer downloads, relatively unrelated to Xcode, accessible by removing the for Xcode - search criteria:


https://developer.apple.com/downloads/index.action