Base game items have the shelves on white walls. Other packs have their own wall textures (if one was available). The wall with the rainbow colored rectangles has a few items from various packs because there weren’t enough to give them their own wall. If items slot to shelves, they are on shelves. If they can slot to tables, they are on tables, If they don’t slot, they are on the floor.
And a room with only debug dishes.