The lovely Plaubel Makina 67 and 670 cameras came with a janky plastic slip-on lens-cap (fits on the lens with or without the hood). The lens-cap is frequently lost or damaged, and prices for used ones are crazy. My used 670 came with the OEM lens-cap, but it was in poor condition, and kept falling off. I searched a long time for an alternative, even going so far as to make one out of leather (ugly but functional). I finally found a great solution: Nikon made a synthetic fabric slip-on lens-cap for the 14/2.8D ED lens, and it is a perfect fit for the 67/670 models. It has a draw-string to tighten it on, and is large enough to entirely cover the hood, or fits on the lens without the hood. It has no model number, but has Nikon part number #4959, and I was able to order one new from Nikon a couple of years ago for a very reasonable price. Alas, the synthetic fabric tends to degrade over time, and used ones I have seen were all in very poor condition (not to mention being more expensive than the new one I got direct from Nikon). Since the 14/2.8D ED was discontinued in 2020, Nikon may not stock the lens-cap anymore, but you should be able to find one with some searching.
Anyways, if you are a Plaubel owner, this is a great solution for upgrading your lens-cap, and it also has "Nikon" emblazoned on it in large silver letters, so makes the Nikkor 80/2.8 feel right at home!