PLX PC19054-AC50PI Interface IC 32Bit Master Chip (lot of 2) - Electronic Components, Integrated Circuits and Op Amps - BMI Surplus
PCIe 3.0 Controller Card 16X for 4 SSD M.2 NVMe M Key Chipset PLX PEX 8747-32GB for each SSD 128G in total.: Amazon.de: Computer & Accessories
Xplained with Paint: PLX chips - YouTube
Hassan Mujtaba on Twitter: "The top end Supermicro SuperO C9Z390 PGW motherboard comes with a PLX chip for extra PCIe lanes. Currently testin it out with the latest Bios rev. Good stuff.
This was an unexpected score. Looks like AMD had a Z490 chipset too... : r/Amd