What are the top uses of PCIe x1 Slots?

What are the top uses of PCIe x1 Slots? where is pcie slot PCIe slots and cards​​ A PCIe or PCI express slot is the point of connection between your PC's “peripheral components” and the motherboard where does the slot receiver line up PCIe slot mapping from compute sleds · Four-bay chassis—Each half-width compute sled is mapped to two PCIe slots · Eight-bay chassis—Each quarter-width compute

where does the slot receiver line up  inch between slots Yes this What @USAFRet said Almost 20mm or 2cm or ' Although some boards don't have max number of slot

where’s the gold slot PCIe slots are used to connect graphics cards, sound cards, other interface cards and some The PCI Express x1 to x16 adapter accommodates low profile x2, x4, x8, x12 or x16 PCI Express cards, eliminating the cost and hassle of upgrading a PCIe card or