We are excited to announce a new feature on the Hub: Favorites!
You can now add resources to your favorites, and organize your favorites into collections!
You can check out the details in our official announcement!
Do you mean the Camera?
If so, there's no option to add back that atom, so what you need to do is to create a new scene to later merge load it into the scene missing the camera (A):
Create a new empty scene
Remove all atoms except the camera and save the scene (B)