This is a very good question, and while I've researched and written about the early years of the Mafia in the US, and looked at Jewish and Irish organised crime in New York as well, I have never come across any references to a German equivalent. This is not to say it never occurred – and in fact, given that at least 6 million German emigrated to the US during the 19th and early 20th centuries, I'd be very surprised if it never did – but certainly Germans were not as prominent as other ethnic groups in organised crime.

To understand why this was so, I'd suggest we need to look at both the way in which German immigration worked, and at the nature of German organised crime itself.

It is almost certainly significant that a high proportion of German immigrants were farmers who arrived in the US in the first half of the 19th century, before westward expansion finally ceased and at a time when land was still relatively easily available and relatively affordable. This meant that large numbers of German immigrants were much less likely to remain in the cities, where organised crime is almost always focused, and much more likely to move on to find and farm land in some relatively remote rural location.

A second significant group of immigrants were relatively well-off political dissidents, many of them fleeing Europe in the wake of the unsuccessful revolutions of 1848. Members of this group were much more likely to remain city-based, but they were often sufficiently wealthy and sufficiently well-educated to be able to take up middle class occupations, and they integrated into US society relatively quickly.

Finally, members of both groups - being northern European and predominantly Protestant - also faced far less prejudice than did Irish, Italian and Jewish immigrants, and hence were much less likely to find themselves living in ghettos and denied opportunities – both key drivers in the development of organised crime among members of other ethnicities.

In addition to all the above, there have been some fascinating posts here at AskHistorians on the nature of the crime that existed in Weimar and Nazi Germany, and these combine to suggest to me that German organised crime, certainly in the early 20th century, was rather different in its methods and aims to the sort of "mob" activity you are referencing. You might find it interesting to check out this recent thread on crime in Weimar and Nazi Germany and this older one on the Nazi period, both dealing with groups known as Ringvereine, both stressing their drive for respectability, and featuring u/Abrytan and u/commiespaceinvader respectively.

The latter thread notes that the Ringvereine

constituted communities for like-minded ex-convicts and members of the German underworld, socially marginalized, who wanted to appear and live in a petty-bourgeois fashion and desired social respectability. Unlike the secretive Italian or American crime syndicates of the same period, the Ringvereine were even officially registered under the Reich Association Law. Members were forbidden by their statutes to commit crimes. But in reality, like crime syndicates elsewhere, the Berlin Ringvereine were engaged in prostitution, the drug trade, the management of the city’s night-life and the ‘offer’ of ‘protection’. Their culture demanded conformity to a meticulous code of respectable behaviour, and dispensation of ‘justice’ to anyone who transgressed its rules... The purpose of the Ringvereine went far beyond professional criminal activity. Their networks provided patronage, loyalty and friendship, offering their members a distinctive, institutionalized and masculine sub-culture.