SKHynix 512GB 256GB PCIe Gen3 x 2 M.2 2242 NVMe SSD HFM512GDHTNG-8310A BA SSD | eBay
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.
64GB/128GB/256GB/512GB 3D nand PCIe Gen3 x 2 NVMe PCIe SSD NE 2242 - KingSpec