I cannot more strongly go with Phillip's last option ... create a Production within Premiere. It's a completely different way of working, so takes a few minutes to relearn. Productions is a folder-on-disc process for Premiere, so there's a Production file in the actual production folder on disd. Within that panel, which is also a folder on disc, you create subfolders to organize either one project, or for my small shop, our entire year of projects.
Within subfolders named for different parts of your workflow, you right-click/create project. So you use subfolders to house project files that are bits of your total production. So say media from X project is in a folder for that in your organization, imported into a project created in that subfolder.
You can simply drag/drop that media into a sequence in another project ... no duplication of assets, no slow downs ... light and fast.
So you can have folders for your resusable assets like audio files, b-roll, graphics, intros, outros.
Simply grab a clip or sequence of this, drop it onto your current project.