No matter what Apple product we are dealing with, a large accessory market is always formed around it. And hubs for Mac are no different.
THE Satechi is a manufacturer specializing in accessories like this, and has just launched an aluminum hub for iMacs and iMacs Pro with a nice difference: it manages to attach itself to the computer housing, through its lower air vents.

The Aluminum Type-C Clamp Hub Pro, which is in pre-order for $ 50, has slots for SD and microSD memory cards, three conventional 3.0 USBs (up to 5Gbps) and one USB-C β all of them facing the front of the machine, in a very practical / accessible way.
Scheduled for dispatch in early January, the hub will be available in silver and space gray to match the iMac [Pro] of the customer.
via The Verge