Isolate Selection
  → Demo Hotkey: Alt + I 
 Mimics the Maya/Softimage “Isolate Selection” workflow at the Objects level.

-  
This is purely a Viewport Visibility modification, display flags of objects are not affected.
 -  
In Cameras all isolated objects get listed in the top left corner of the viewport:

(→ Unfortunately this does not seem to be possible in orthographic viewports…) -  
Try to not save scenes in a viewport-isolated state.
The isolation state “sort-of” persists in a weird way, and I’ve found that you often need to close and re-create the “Scene View” after scene load, to fix things.