CORSAIR FORCE Series MP300 SSD 120GB 240GB m.2 2280 NVMe PCIe Gen3 x2 M.2 SSD 480GB 960GB Solid State Storage 3,000MB/s laptop - AliExpress Computer & Office
Patriot SCORCH M.2 2280 512GB PCI-Express 3.0 x2 with NVMe 1.2 Internal Solid State Drive (SSD) PS512GPM280SSDR - Newegg.com
Amazon.com: PCIe Gen3 x2 USB 3.2 / 3.1 Card ASM3142- PCI Express to 4-Port Type C HUB Internal Expansion Card Controller Adapter PCI Express Card Desktop PC Support Multiple INs : Electronics
SilverStone Technology ECS06 6 Port SATA Gen3 (6Gbps) Non-RAID PCI Express Gen3 x2 Card - Walmart.com
I harvested a PCIe Gen3 x2 NVMe 1.3 SSD from my older laptop, the problem is that its length is short. I've held it in place with some tape, it should hold.
Western Digital SDAPMUW-512G 512GB PC SN520 PCIe Gen3 x2 NVMe V1.3 M.2 2242 Internal Solid State Drive - Newegg.com