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.
SSD PX400 NVMe PCIe Gen 3 x2 - GOODRAM
Kingbank 128gb 240gb M.2 2280 Pcie Gen 3x2 Sata Nvme 128g 240g Desktop Laptop Server 2 Internal Pc Solid State Drive Ssd - Solid State Drives - AliExpress
Amazon.com: QNAP QM2-2P2G2T2 x PCIe Gen3 M.2 NVMe SSD & 2 x 2.5GbE Port Expansion Card to Enhance Performance : Electronics
SDAPTUW-256G Western Digital PC SN520 256GB M.2 2230 Nvme Pcie GEN3 X2 SSD NGP80 M.2 SSD / Solid State Drive - Walmart.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
Western Digital SDAPMUW-512G 512GB PC SN520 PCIe Gen3 x2 NVMe V1.3 M.2 2242 Internal Solid State Drive - Newegg.com
Apacer Launches AS2280P2 M.2 PCIe Gen 3 x2 SSD
960GB Transcend JetDrive 820 PCIe Gen 3 x2 SSD for Select Mac Producs | eBay
Corsair Force Series Mp300 Ssd 120gb 240gb Nvme Pcie Gen3 X2 M.2 Ssd 480gb 960gb Solid State Storage 3,000mb/s M.2 2280 Laptop - Solid State Drives - AliExpress
What is the difference between PCIe Gen 3 X2 and X4 SSDs? Can these two SSDs be used for laptops that support the PCIe interface? - Quora