If there was, what are some of their most known operations?
In terms of militant armed resistance, no. Rather, never on any important scale. Ed Houston mentions "German Resistance" aiding the 2nd Armored division during the final battles in the Ruhr. However, he's the only author I've read who's used the term and frankly its most likely a colloquialism for individual Burghers aiding Americans approaching their town.
Resistance of note in Germany came from intellectual quarters and from within the military itself. The July 20th plot, as well as all the previous assassination attempts by dispirited/disillusioned Officers are fairly well recorded. This resistance was generally led by younger, aggressive Officers who realized that a coup would only work if Hitler was killed, not merely deposed. Sadly all attempts failed. Beevor also mentions the presence of "communist cells" at work in the Wehrmacht. This is believable, given that many of the Generals captured at Stalingrad became active Communist sympathizers during the course of the war, such as Seydlitz-Kurbach or Paulus himself.
Non-violent resistance was also present from the Catholic Church and student movements. The most noteworthy being the White Rose movement. The movement was largely limited to the handing-out of pamphlets which called for the deposing of Adolf Hitler. The Gestapo rapidly found and executed the ring-leaders.
If anything more comes to mind I'll edit it in. I'm hoping a more specialized flair notices, just don't want to leave you completely answerless.