EverQuest II's art style can generally be summed up as realistic-high fantasy. In a broad sense, our materials, color usage, silhouettes and scale are grounded more in realism than stylization, with occasional exceptions.
Here's some information that will help you create an item that works well in EverQuest II.
If you create an item and think it will look out of place within EverQuest II, then it probably will! Players will enjoy them more if they don't look too out of place. Try to match the feeling of the game to ensure your best chance at getting your item into the marketplace.