Although I'm not entirely sure how accurate this information is I'm pretty sure I've heard some time ago (maybe in association with the British Museum exhibition and BBC Radio Series 'Germany: Memories of a Nation' back in 2014) that there are over 1400 different types of sausages in Germany and to be honest, I'm not even THAT surprised.
So my 2015 New Year's resolution was to try them all. I failed miserably.
Still, for me a visit to Germany isn't complete without a Currywurst (best eaten in Berlin or the Ruhrgebiet), or a classic Weisswurst in Bavaria, with a pretzel, sweet mustard and of course a beer (all consumed before midday).
And whenever I'm in Frankfurt, a Rindswurst from Gref-Völsing is a must. For convenience you can get them from Schön's Wurstwaren in the Kleinmarkthalle which should be on everyone's list for Frankfurt anyway. For a quick snack (sausage of course) you could try a sausage from SCHREIBERS, also in the Kleinmarkthalle.