The "custom" quest gives your graphicless helm a graphic. This is the opposite of what you are looking for.
As a general rule most things called "Crown" have no graphic. Eg Froglok Crown, Metal Linked Crown, Crown of Forbidden Rites, Akkirus's Crown of the Risen etc.
There are other helms that do not have graphics, Ornate for example, but there is no sure way of knowing unless you know someone with them.
In addition some things have no graphic on one race and graphics on another. Some helms with graphic look stupid on one race and good on another due to the way designs change with race and sex. If you want to be really sure then get it modelled by someone of the same race, sex and hat size as your character.
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Wherever I go - there I am.