I loved the original model, but needed more than four slots, and also wanted to be able to mount it vertically on my metal desk. I smooshed three of the original together (to create 12 USB slots) and added extra thickness to the base to allow space for two countersunk 12x3mm magnets that I had lying around to press fit to the back. The magnets I have are similar to these: https://www.aliexpress.com/item/1005003633257380.html?spm=a2g0o.productlist.main.1.16d2bOqsbOqsay&algo_pvid=ab4197ef-ab46-41c9-beb7-2656c6a6bd18&algo_exp_id=ab4197ef-ab46-41c9-beb7-2656c6a6bd18-0&pdp_npi=4%40dis%21GBP%214.79%212.87%21%21%215.99%213.59%21%40211b80d117219440520323503ea392%2112000026580898684%21sea%21UK%21705562622%21X&curPageLogUid=6vPbpLsRTr6z&utparam-url=scene%3Asearch%7Cquery_from%3A

Since I assume most people won't have the same magnets knocking around, I've included the STL for the model without the holes. It only takes two minutes to add holes for your own magnets in Tinkercad if you wanted to. 

Printed on Ender 3 V3 SE

PETG

0.2mm

10-15% infill

Supports for magnet holes.