Amazon.com: REDLUX PCIe 3.0 to NVMe (4) M.2 Adapter for M.2 (M Key) SSD, X16,Compatible with PCIe 3.0 Motherboards and Backward Compatible with PCIe 2.0 and PCIe 1.0 : Electronics
M.2 PCIe SSD to PCIe Adapter
Synology M2D18 Storage bay adapter Expansion Slot to 2 x M.2 M.2 Card PCIe 2.0 x8 - Office Depot
NVMe PCIe M.2 NGFF SSD to PCIe x1 adapter card PCIe x1 to M.2 card with bracket - AliExpress
PCI Express M2 Adapter PCIE M2 SATA Adapter SSD M.2 SATA-Base B key Quad Ports M2 to PCIE Adapter PCI-E X1 Marvell 88se9235 Chip - AliExpress
Amazon.com: Tripp Lite U.2 to PCIe Adapter for 2.5″ NVMe U.2 SSD, SFF-8639, PCI Express Card, Supports U.2 SSDs and SATA I/II/III SSDs & HDDs, Backward Compatible with PCIe 2.0 & 1.0,
PCI-E 3.0 x1 Lane to M.2 M-Key SSD Nvme AHCI PCI Express Adapter Card PCIE SSD | eBay
Amazon.com: NVMe PCIe Adapter, RIITOP M.2 NVMe to PCI-e x4/x8/x16 Card with Heat Sink for M.2 (M Key) SSD 2280/2260/2242/2230 [Upgraded] : Electronics