Searching for Original Vanity Light Frosted Glass Cover

Here is the photograph ( https://ibb.co/Hz3HVJ7 )

Best option is eBay but you can also setup a search on Invaluable and/or LiveAuctioneers to notify you when something that might work shows up.

+1 on hunting for an original one (including OfferUp, etc.). That said, Progress Lighting (and a few other lighting manufacturers) make one that's pretty darn close to what the original one looks like -- look on the interwebs for "channel light".