Duplicate the Design containing the component that you need to use often see:
https://discourse.shapr3d.com/t/create-body-from-absence/7899/5
Then as @hamedtopic says above delete the objects not required.
Every Design needs a home [read workspace] it really is simple and efficient, the hard bit follows.
If you are going to create a lot of Designs of any kind, I certainly do, it is paramount that a good Filing System is set up using the iPad Files App, it is rather more tedious than Finder or Explorer but it works.
Little point in working hard on Designs and not being able to find them when needed. Done properly good filing practice will enable the required Design to be efficiently Imported in the the current Project.
Organising Designs so that lots of Bodies that are related are placed in Folder(s) makes bulk Selecting, Hiding, Unhiding and Deleting very easy.