There is a huge class of money that is created when a bank issues an covered bond (backed by real estate), which is bought by a central bank. The money is both

There is a huge class of money that is created when a bank issues an covered bond (backed by real estate), which is bought by a central bank. The money is both created from thin air and at the same time connected to the underlying assets in the bond. I'm leaning towards the opinion that it's more "air" than "matter" in that case, but you could argue that it's somehow reflecting the underlying economy somehow.