As Sceadwian said, UL lists only complete products. There are UL recognized components. But the components that they will recognize are limited to specific, well defined functions such as connectors, fuses, wire, switches and such. Their use makes the final product certification testing simpler, provided their application fits within the accepted limits of the component specification.
Microcontrollers, by their very nature, are not well defined functions. They are entirely dependent on the code burned into them. The most you could expect for UL recognition for a uC, would be that the encapsulation material was nonflammable.