I have a 2012 iMac that I'm currently using as a file server. I need to connect several 3.5" hard drives to it, and its USB 3 ports are currently used up with other devices. So what I'd like to do is connect something like an external enclosure with multiple drive bays (as many as four) to the Thunderbolt 1 port of this iMac.
So far I haven't been able to find a singular device that'll let me do it, and I'm not sure if I can pull it off with adapters. For example, there are now many USB-C multi-bay hard drive enclosures, but I'm not confident I'd be able to use it with a 2012 iMac.
Is there either a) a device, possibly an old one I could get used, that connects multiple hard drives to a Thunderbolt port, or b) an adapter I can use to connect a more modern multi-bay enclosure?