the Swabians
there are more names for Germans coming from their various countries.
Bambry - Brandenburg settlers, farmers and affluent burghers (burgman - bamber, I think they hadn't mind)
Prusaki - Prussians
Dojcze - keeping the pronounciation
Niemczur/Niemra - twisting the Niemiec name
Germaniec - a crib from Russian
Niemiaszki - a diminutive term, both nice and mean. Like in (aww, those neighbours of ours, tut!)
Russians: Rusek, Ruski kacap (but don't use that one, originally from Lviv: idiot), Moskal, Moskwicin
Czech: Pepiki, Pepiczki, Bracia Czesi (same as Niemiaszki)
Ukrainian: Ruski (offensive enough hehe)
General - anyone from the West: Pludrak, Pludraki, from wearing those pantalones. 'Shorty-pants', 'culotes'.
Within Poland cities offend one another this way:
Kraków - centusie (penny pinchers)
Warszawa - Warsiawiaki, Stolyyca (mocking the pronounciation)
Poznań - Pyry (potato eaters
Częstochowa - medaliki (religious medals, as in show-offs)
Katowice/Wrocław - Hanysy
and possibly more. The best one is from Olkusz. My friend got stopped by the Police for speeding within city limits, and offended them thus: 'Honey, where do you see a city?!'
There were also stanowe names, like strata names, class names:
Szlachta - pany
chłopi - chamy
mieszczanie - łyki
Żydzi - parchy
others - bieszczadniki
More here: forum.wordreference.com/showthread.php?t=1190297