Update for Xcode 10
Keyboard shortcuts to open the object library:
Command + Shift + L
Old
In the object library, you can set focus directly on the object, simply by pressing a specific key for the object from the keyboard,
Focus on the object library โโฅโ 3 / Command + Option - Ctrl +3
If you want UIButton, just press B , and focus on UIButton.
You do not need to search in the search bar every time.
Or
You can change the gridview of the object library so that you can see more controls at the same time, 
Than you will see how

source share