This is something that is hotly debated. There are some proto-Nazi trends in pre-Great War philosophy and culture, but it's debatable whether they are greater or lesser than other countries.

Nazism owed something to 19th century German romanticism. You've probably heard of the Nazi's affection for Wagner, right? It's not just because they liked his music, Wagner was rooted in a philosophical movement that lionised athleticism, heroism, and a gothic past of legendary figures engaged in mythic struggles. This romantic movement was also quite strongly connected to the German nationalist movement, although they weren't the same thing. At its heart, the romantic movement was anti-Enlightenment/anti-Renaissance, and that resonated powerfully with Nazi medievalism. However, Germany wasn't the only country that had a romantic/nationalist movement, and there were some aspects of the romantic movement that ran counter to Nazi ideology - while romanticism lionised mythic conflict, it could also be quite pacifist and nurturing.

There's also a tradition of German anti-semitism that predates the Nazi party significantly. For example, a Prussian officer in the early 19th century was refused promotion to Captain if he didn't conver to christianity, and there were popular outbursts of antisemitic violence in some southern German areas. Wagner said some pretty negative things about Jews. On the other hand, there were also powerful philosemitic tendencies in German culture - Theodor Fontane wrote a story praising a Jewish soldier serving in the Prussian army during the Napoleonic wars.

The last, and probably least influential, of the proto-Nazi tendencies was the occultist anti-semitism of figures like Houston Chamberlain and Karl Luger, Mayor of Vienna (I'm presuming you are asking about Germany as a cultural entity, not a political one). These guys tend to get the most attention because they seem to most resemble proto-Nazis, but their influence was comparatively minor.

It's interesting that a lot of the most important proto-Nazi thinkers were actually not German at all. Specifically, the earliest wave of fascist ideology came from French authors during the 19th century, notably Walter Gobineau and Charles Maurras. I would add Jules Michelet to this list, controversially, but in his writing about France as a divine entity I feel he was paving the way for the extreme nationalism of the later Nazis, although lots of other authors would disagree (and unlike Gobineau and Maurras, there's no sign that any German thinkers were ever influenced by Michelet).

In summary, while there were some significant pre-Nazi tendencies in Germany, many of them were pan-European, and it's hard to say that Germany was uniquely fertile ground for a totalitarian nationalist state, although it was certainly fertile enough.

NB: Some people would say Nietzsche was also an important precursor to Nazist ideology. Some people will say that Nazi idealisation of Nietzsche was appropriation, but I think his thought does have some significant connections to Nazi philosophy - not that Nietzsche himself was a Nazi, but what he said does flow into Nazism fairly naturally. However, Nietzsche was kind of a cultural island - although he was German, his thought didn't really play a role in wider German culture outside of a narrow academic elite (in contrast to Wagner, who was very much immersed in German culture - or perhaps the opposite is a better way to put it!).

Sources: Christopher Clark, 'Iron Kingdom' (Prussia), Frederick Beiser, the Romantic Imperative (Romanticism/Wagner), Andrew Wheatcroft, The Hapsburgs: Embodying Empire (Austria), Francois Huguenin, L'Action Francaise: Une Histoire Intellectuelle (France)

I posted this a while back that touched on what you've asked here. I listed some sources at the bottom.