There are "sandwich style" SFF cases which mount the GPU parallel to the back of the motherboard, if that's what you mean. It's more for space than for airflow

There are "sandwich style" SFF cases which mount the GPU parallel to the back of the motherboard, if that's what you mean. It's more for space than for airflow, but you can get good airflow too with the right design (e.g. standoffs/separation, exhaust fans).