The basic board design for a PCIe PCB is highly reminiscent of that of PCI cards. Both use an edge connector with a similar layout. PCIe edge connectors are 1.6 mm thick, use a 1.0 mm pitch ...
OrbitIO and SiP Layout enable automated IC/package/PCB interconnect design and optimization ... 264, USB 2.0/3.1 Gen 1, 10/100/1000 Ethernet, Serial ATA, PCI Express, and programmable SerDes, etc.