TairikuOkami said:
To complete my previous statement, I meant the original location of .ico files.
I believe, that the ico's location is saved within the shortcut's properties itself.
So you need to backup shortcuts and place .ico files to the referenced folder.
If 10 can not find them, it will probably reset them and will use default icons.
Thanks. The icons that are 'custom' (not Windows .ico files) are all saved in the folder for which they were created, which are all backed up redundantly on storage drives. So I could reassign each one, but there are probably dozens. That's why I was hoping for an .ico database solution.

Right now my primary docs on on an internal storage drive, assigned G:/.

One of the places I back that up is to a WD portable external drive that I use with my laptop. When connected to my laptop, I assign it G: there as well. In doing so, I see all the same icons when on my laptop that I see on my desktop.

I was hoping that as long as that internal storage drive on my desktop is called "G" as well, that those icons would be seen in Windows 10.