adapter slots

What are practical options for adding card slots to a motherboard? My ASUS ROG X670E Strix-E motherboard has only 3 card slots: 2 x16 and 1 x 1 The x16 slots are used for the GPU card and a SATA port extender card. That leaves just 1 X1 slot, which I use for more USB A and USB C ports, which...