Dream island's codes

Hi, I just discovered that you can only use your own designs you already have on Dream Islands

I was wondering if anyone has any free design slots so they could download, or perhaps already have some Citycore designs and could bring them to my Dream Island

I heard that no one has to stay in the dream and can just drop the codes without any further effort

That would be incredibly kind, because I simply don't have any more space for designs after completely decorating my main island