You can toggle between your different client accounts in the ‘Import Campaigns’ screen. From there you can import any combination of campaigns from any accounts associated with your Business Manager account for Facebook or MCC account for AdWords. 

For Facebook campaigns you can also sort your campaigns by 'status', that is, if they are active or paused.

For AdWords, you can use the search bar at the top of the import campaigns screen to search for the name of campaigns you wish to import in.