Chinese manufacturer Cloud Workshop has released what I can only describe as neck warmers for Nikon lenses. The story was broken by Nikon Rumors, and I’ve since been able to locate a version for the Nikon 58mm f/1.4 G on Chinese e-store Taobao, while a Nikon AF‑S 105mm f/1.4E ED cover is also said to be available.
If you’ve ever used an FTZ II adapter, you’ll know that the peripheral necessarily elongates the mount end of the lens in question, which can look rather awkward, especially if the lens is rather bulbous.