People sometimes insure the strangest vehicles. The popularity of school proms has encouraged a competitive spirit amongst kids to arrive in the weirdest possible vehicles; milk floats, fire engines, miniature trains, amphibious vehicles, streched (and we MEAN stretched) limousines, and even military tanks have been converted to means of transport for the adventurous and the imaginative. All these require insurance to drive on a public highway.
On the other hand you may own a very rare and exotic American car. Or perhaps a kit car that you built yourself onto an old car's chassis. You may have a collection of military vehicles. Your car could be a fairly modern one but heavily customised to reflect your own individuality. You may have taken a fairly standard car and stuck an enormous engine in it.
Then again you may have a road roller, a large excavator, or a huge dump truck. They will all need to be insured before they can be taken on the road legally.
To make life more interesting, the novelty vehicles are hardly likely to be used just for driving to and from the office, or taking the family out for a picnic! They are far more likely to go to shows, take part in festivals, perhaps even race or be used for adventure sports. The heavy equipment may have to switch from driving on a road to climbing in and out of deep quarries or churning through deep mud. Every one of these vehicles will have a different set of risks, and will need a different type of insurance policy.
There is no point going to your favourite price comparison site and tried to get cover for a JCB, a Chieftain tank or a Green Goddess fire engine! All these vehicles need specialist insurance, arranged by a specialist broker.