If I get a Project where I have useful looking pieces but not usable immediately I make the Project longer and park them out of the way at the end.
When needed, Select all (ctrl + A) then press P and press 2 and there they are.
Audio has the Pool. Maybe that should be extended so dragging audio and midi material there would enable parking.
Ha! Cheers for that link. There must be a few hundred of those little solutions hidden in Cubase. 