In War3 you could select 1 item per type and paste it on a new map liek 1 Unit, 1 Item, 1 Ability, 1 Buff. In SC2 you cannot copy and paste more tha one type but you can paste several items in the same type. E.g several units or several Items or several Actors.
So one way is this, the other way is using a mod and loading stuff from it.