Sometimes plates come up for sale that are not vehicle number plates at all. This photo is of some non-vehicle plates.
The top row has three probably 1970s Abu Dhabi house number plates. Made the same way as vehicle plates, they are not however.
The second row has an old Bahrain house number plate (or possibly from some street furniture – electric boxes, poles, etc), two sample plates for an Abra – the boats that carry people across the creek in Dubai and a plate from an Iraqi museum (translation: Museum 575. They are the Sumarians in the valley of the two rivers, south of Baghdad capital of Iraq) – no doubt liberated from a museum exhibit.
The third row has two Saudi Dhahran Electric Power Company plates from electric poles or transformers and a Saudi shop number.
The bottom row has a plate that translates as ‚Kingdom of Saudi Arabia‘ over ‚pipeline district 40‘ – no doubt from a building and a Ras Al-Khaimah house number plate.
Everyone should join a plate society and check what they are trading for or buying with the available records of that society although some societies have better detailed records than others and may specialize in certain areas of the world only.