All feature template assets can be used in your own projects. That means anything found in the UI folder can be migrated into another project.
Only the Textures folder can be migrated on its own, but all device-related assets must be migrated for them to work with the device.
Do the following to migrate assets:
In the Content Browser, select the Asset(s) folder from the asset list.
Right-click and select Migrate... from the Context Menu. This opens the Asset Report window.
From the Asset Report window, select the assets you want to export, then click OK.
All assets inside the folders will automatically be selected. If you don’t want to migrate all of the assets, deselect the assets you don’t want in the list.
Search for the project folder within Fortnite Projects where you want to place the assets.
Open the project's Content folder and click Select Folder.
The asset folders import into the new project Content folder.