Any adapters for a x16 PCIe slot split in multiple smaller ones?

Every PCIe slot supports its own number of CPU lanes X16 has 16 Lanes support, X8 has 8 Lanes support, X4 has 4 lanes support and x1 has

PCI Express x16 to x16 Slot Riser Card Extension Cable

pcie 1x slot It's a slot of x16 size but electrically x4 This

pcie 4 in pcie 3 slot ssd A x8 card will work in an x1 slot, but will be limited to x1 speeds A x8 card will also work fine in a x4 slot It will be limited to x4 speeds