This is a Flash I created in "Onshape". I did create this for my Flash Drives; however, if you click on the link at the bottom it will redirect you to the document. You can then create a copy and design it for your Flash Drives. If you don't know how to do this then please contact me and I will design it for your Flash Drives. I also have created one of these but it also has slots for SD Cards.
https://cad.onshape.com/documents/f15b62167a0b2912fde785e5/w/3535ea751aa07456cdf73ca6/e/bf2a104fcdd38b2ddf30a8bd