@jotunheimed If you have the sims in any accessible save, you can save them to your in-game library now and rebuild the content.
The Tray folder is exactly where this content is stored, so anything you deleted from Tray will disappear from the in-game library accordingly. Each library item has several corresponding Tray files, and you can see which ones go together if you sort by date modified.
You could transfer the older Tray files from your old computer again if you wanted. There's no reason they shouldn't work now if they did before.
