Does anyone know of a Thunderbolt 2 (not type C or thunderbolt 3) to usb 3 micro b cable?
Thunderbolt is a wholly different connection protocol from USB--it's more like external PCI-Express--so any such cable would need a USB controller built-in. It's almost certainly possible to miniaturize this into a single cable, but I doubt the demand ever existed for a commercial part to make sense; additionally, performance would still be limited by USB's capabilities. Your best bet is probably a Thunderbolt "hub", for instance this USB and eSATA model, or a larger dock such as this one.