M2 Standoff and Screw Set (Asus, SSD M.2) 21646 [21646] : Metric Screws!, We have the screws you need!
How can I replace a broken M.2 SSD mounting standoff for my motherboard? - Super User
So I bought an m.2 ssd. At first I didn't find this standoff and screw but I think these are the right ones (they came in the motherboard box). The screw in
Michaelia M.2 Standoff and Screw for M.2 Drives,Asus Motherboard M.2 Screw + Hex Nut Stand Off Spacer(3 Sets)+1 pcs Screwdriver : Amazon.co.uk: Computers & Accessories