I haven’t seen many English language sites from detectorists in Germany, but i found this one recently. He has certainly made some interesting finds, including a sub-machine gun from world war two!
It is a real shame that there aren’t more english language german metal detecting sites (or a great shame that I didn’t pay more attention in German class at school), as Germany has a very interesting history.
It would be amazing to find something that had belonged to a member of the Germanic Tribes who defeated the Varus Legions at the Battle of Teutoburg Forest, probably the most shocking defeat of a roman army in the entire history of the empire, or even a coin or piece of armor that had belonged to a fleeing roman soldier.
The site of the battle Teutoburg forest was actually rediscovered by a British metal detectorist, Major Tony Clunn, who was serving with the British Army in Germany.