A folder with a ton of files was accidentally deleted from the file cabinet. Does anyone know if it is at all possible to retrieve them, perhaps maybe with the help of NetSuite?

I would open a ticket with NetSuite and see what your options are to restore the files. the other option you could try is to refresh your netsuite sandbox and see if the files are still there. the files being there would be dependent on what time your sandbox refresh is

Thank you