I'm writing a research paper on Sept. 1, 1939, the beginning of Germany's invasion of Poland and start of WWII. It got me thinking if there were any rebels that would try to mess up the Germans, and if we have a record of them.
...are you asking with specific reference to 1939 or at any point throughout the war?
The Home Army was the largest resistance force in Europe at that time. From the start they sabotaged German war effort, attacking trains and assassinating German leaders, providing intel to Allies (most famously on V2 rockets), culminating in the Warsaw Rising in 1944.