I'm going to answer this in hopes that it is not a blatant troll...
Anything that is not a unique item, or "not dropped on pk death" will not drop. These include item shop items of course, but also include unique quest items. Many quest items that are not listed as "not dropped on pk death" or "unique" don't drop, despite not being catagorized as either. Marriage food, proof of myth, many event reward items, siege war packages, etc. are also unable to be pk dropped.
There are items in the item shop that give up to8 pieces of equip the "prevent hijack" status -- this is the same as "not dropped on pk death".