German naming conventions of weapon systems (including, but not limited to ships) are a bit special, I think. They are, as a matter of fact, a scandalized subject to public debate in prime time news every other year (because there is e.g. still a Field Marshal Rommel Barracks which some deem inappropriate because he was a high-ranking General with the Nazi-Wehrmacht).
In general, we do not use names of persons (except for bases; and these bases are the main reason that the debate I mentioned goes on; also the Air Force Wing responsible for Executive Transport has some civilian aircrafts named after early chancellors) but rather places or animals. Concerning the ships, we tend to name them after our federal States (the newest frigate class named “Baden-Würrtemberg”-class) or (big) cities (the newest corvette class named “Braunschweig”-Class). Interestingly, our captial city, Berlin, lends its name to the class of Replenishment Ships currently in use.
We also had ships named after islands, or maritime fauna. Birds seemed to be especially popular for a time, but there were fish seafood (yes.) and even land animals (e.g. Lion or Puma, the latter being now the name of an Infantry Fighting Vehicle, IFV). Now, it’s mostly cities and some rivers.
So, if you want a random list of possible ship names following the tradition of nowadays German Navy, I would recommend to draw it from the List of Cities and Towns in Germany, the List of Rivers of Germany. You could also just take literally any animal to name a ship, though. 
The problem with persons is that Germany was unified from countless scattered, little but sovereign principalities to the German Empire in 1871. The Empire started WW1 (this is debated by scholars of history, recently, but anyway…). The Empire then was reorganised to become a democracy in 1918, but this democracy failed to defend itself from the Nazis rising in power in 1933; the Nazis eventually started WW2 in 1939. Todays Germany, the Federal Republic, was reorganised in 1949. I think, the majority of Germans would say that the period from 1871–1945 (or 1949) is not apt to spark tradition. Luckily, almost everyone agrees on this for the period 1933–1945.
This leaves us for the last seventy years or so. There is not much to draw off and post-heroism seems to be part of our culture, now. So, naming a warship after e.g. Chancellor Angela Merkel is kind of unthinkable in Germany. I think this holds also true for Chancellor Helmut Schmidt (who seemed to have been accepted even by his political enemies and has served in the Wehrmacht and the Bundeswehr) or President Weizsäcker, who was one of our more notable presidents.
But if you want a list of German personalities that could lend their names to warships, I would recommend to start searching within the resistance against the Nazis. The List of Members of the 20 July Plot could be a start, other notable organisations were the so-called Red Orchestra or the White Rose. I, personally, would think about adding Fritz Bauer to the list of important German personalities. I am not sure whether he would have liked having a warship named after him, though.