Do you regard the Polish Communist Partizans as heroes?
In communist times they were glorified and their role was greatly overemphasized. Later it turned out there were few of them compared to AK. Besides, they often dealt with dubious activities. Simply speaking, some communist partizans were renegades who often prefered to attack Poles instead of Germans.
However, when they fought against Germans, they could be extremely effective. There were a few famous battles in which AL units played a major role and even defeated Germans.
Unfortunately, those battle links are only in Polish:
At least they didn`t collaborate with Germans as openly as nationalist NSZ.