Walt,
I used to collect German Bayonets, and the best place is scan Ebay for it, when you want to have a WW1 bayonet, there is the;
model 1898/05 "Butcher, which is there in a few models (common WW1 model):
1898/05 aA (alte art) old design (wide ears at the muzzle area of the pommel, and/or a flash protector between the grips).
1898/05 na (Neue art) new design (small ears)
1898/05 Sage (with sawback) in both models to be found
1898/05 Sage abg (Sawbck removed by grinding away the teeth)
M1898/02: Aa and Na and with sawback (long slim blade)
M1884/98/III:Bayonet used in WW2:
earlier model with wooden grips, later models with bakelite grips
navy marked models, with a "O"for Ostsee issued bayonets.
navy marked models with a "N"for Nortsee isued bayonets
Police issued bayonets (eagle with number on it, no regular numbers)
early models WW1 etc (model 1884/98/I en 1884/98/II)
Then there are the dress bayonets, but that will be a chapter on his own.
For all bayonets try to find a match between the scabbard and bayonet, (serialnumbers). Be aware of the newly made scabbards, and renumbered bayonets from Portugal, the do get on the marked.
If you have questions about a bayonet, just ask, i used to own over 200 of them in the past.