I can't find any HDD Rack for Seagate Backup Plus so I made it myself.

This is a modular stackable rack for Seagate Backup Plus 2TB and 4TB only (76.5 and 78.5 wide) . It can be stacked as many as you want with the top and bottom cover.

Files are in low quality since I use Shapr3d free version to make that I can't export in higher quality so you don't have to print them in fine or better setting but I think they are quite good enough.