I do not even know yet whether I want to go here. There are lots of them. Throughout its history, G&G has been the major supplier for G&L, but others like TKL (I suspect especially for the thermoplastic form fit cases) have also been used at times. But for a start, check out this post on the Guitars by Leo (GbL) website and scroll down a bit. You might be familiar by now with the author. In addition, the GbL Gallery contains a separate G&L instrument cases album.