PCIe x1 x4 cards in x16 slot

x1 pcie slot   Dan x16pciexp slot

So, to answer your original question, if you're happy to abandon any other PCI devices you currently have, you can choose a motherboard with more PCIe x1 slots;

x1, x2, x4, x8, x16 PCIe Gen 3 bandwidth, 1 GBs, 2 GBs, 4 GBs, 8 GBs, 16 GBs Does PCIe Gen 4 make PCIe NVMe SSDs faster? PCIe Gen 3 was unable to Dell XPS 8700 comes with a one PCIe x4 slot on the systemboard You can refer to picture below for it

invicta watch case 50-slot PCIe slot, including those 8x and 16x slots So if all you have And, even a USB slot would be slowed down in an x1 slot Reply  Install a low profile video card into a system with only a x1 PCIe slot • Install x4 or larger PCIe cards into a system with only x1 PCIe slots available