What are PCIe x1 Slots Used For?

however both x1 cards work in desktop's pci express x16 slots, plus, a x16 AMD GPU card works on unmatched board as well both x1 cards are wifi

Hi everyone, I want to upgrade my custom build TrueNAS to 10GbE However, I find that the motherboard only remain a PCIe x1 (in x16

pcie m2 slot PCI Express X1 to X16 Low Profile Slot Extension Adapter - PCIe x1 to x16 Adapter - PCIe x1 to PCIe x16 slot adapter

pcie slot gpu I cut open the back of a x1 slot on my motherboard to allow me to fit a full size GPU