Before you delete anything, check whether you still need these files. The steps below remove material map folders and library files from your drive. Any Cinema 4D scene that used those materials points at those exact files, so deleting them leaves those scenes with broken material paths — and Cargo cannot restore them, because Cargo never had them.
If there's any chance you'll reopen an older project that used these packs, keep them. If you've archived those projects for good, or you only want to free space and re-download later, carry on.
To remove items from your installed List on the HUB please follow steps below:
Go to Greyscalegorilla menu in Cinema 4D, then click Greyscalegorilla HUB
2. Then click on the "Installed" tab. Hover your mouse over the pack you want to remove and hold the Left Alt key (for Windows) or the Option key (for Mac) on your keyboard and while holding the key, right-click with your mouse to the pack name and select "Remove From Install List"
This will remove the pack from the list and Plus Library so you can download again from Stock Assets tab.
However, this only removes the pack name. You also need to delete the related maps folder and library file from your GSG assets folder.
Examples:
GSG_Assets\materials\gsg_mc01x_packname_maps
GSG_Assets\materials\GSG_packname_Materials_Octane_1A.g2lib
After removing from HUB list and deleting related files, please restart Cinema 4D.
Then you can download again from HUB "Stock Assets" tab. After downloading don't forget to hit the "Install Assets" button on the right corner.