You can find them with some Googling (but be warned that can quickly put you in unsavory company).
As a side note on this, you may find that the Luftwaffe has a disproportionate presence on the list of air aces for WW2. You might be tempted to draw the conclusion that the Luftwaffe was full of sharp pilots, or that it deployed unstoppable machines, or that its opponents had neither of those things. While the Luftwaffe did have some excellent planes, and it certainly had a number of skilled expert fliers, these results are also a direct result of policy: Germany kept its veteran pilots in the air much longer than other nations did.
German strategy in general depended on a series of overwhelming and fast campaigns which would prevent any one enemy from pinning German forces down while another enemy gathered the strength to attack. Germany's leaders knew they were sorely outmatched in any lengthy war of attrition. This is why they tried to put every available pilot in the air, and also why training replacement pilots and building a force sustainable in the long term was a lower priority. While the Luftwaffe's best pilots were given numerous opportunities to fight (long after an American or even a Soviet pilot would have been rotated to flight training duty), many of its novice pilots were sent into combat with less than a third of the training American airmen received. Germany lacked the personnel, fuel, and time to effectively train its pilots.
Well, first of all pretty much all those stories are often hard to verify, the same is true for stories about allied "one man armies". If unique things happened they were often exaggerated even more for the propaganda. This is particulary true for "heroic" actions by fallen soldiers.
The best documented action is likely Wittmanns attack in Villers Bocage during the early stages of Normandy. While the accounts of the attack were distorted by German propaganda and Post War books its still impressive. He basically attacked British Forces in Villers Bocage on its own while the rest of its company was a little behind, during 15 minutes he knocked out several enemy tanks maybe up to 14 including close urban combat while being under fire from several concealed anti tank guns. The important part here that this battle and to a significant degree Wittmann himself had a major impact on the decicions making of the British officers. Eventually they decided to withdraw and leave a favorable position. Historians agree that withdrawing in this manner was incorrect and the results of the morning Battles at Villers played a curcial role. Most of the staff was later sacked for their handling of the battle. While the British Leaders misinterpreted the situation Wittmann helped to make them misinterpret the situation so it could be argued that a single tank commander had significant impact on the early Normandy Battle this is the closest you can get to "one man army". Iam not saying Wittmann made the British Army retreat but his actions had influence on the decision making and eventually the 7th Armored Division choose to retreat and enter a long costly static battle around Caen.
Some other examples are.
Franz Staudegger: The first Tiger commander to be awarded the Knights Cross. He supposedly engaged a group of ~50 T-34 and destroyed ~20. Its documented in the war diaries of the unit and the knights cross gives some credentials to the claim but like always its unknown if it really were 20+.
When it comes to tank commanders examples like Staudegger and Wittmann are not that unique but this is partially explained by the specs of the Tiger tank. However Wittmanns action is notable for the aftermath.
While not as impressive as Audie Murphy since the achievements were spread over a long period of time most of the higher German Aces had more impact on the war than entire enemy squadrons. Same can be said for some tank crews.
Special mention here to Hans-Joachim Marseilles. He flew mostly against Western Allies reporting 151 claims against them. Most of these claims are cross referenced. Such records often get explained by German pilots flying against inferior foes ( Red Air Force ) and racking up kills and experience. Marseilles did it against Western pilots and in an impressive way. He also only flew for a pretty short time frame before he died in an accident. Its a matter of opinion but i consider him the most impressive pilot of WW2.
On top of my hat the closest to a real life "Fredrik Zoller" could be Fritz Christen if his account of events is true. He is said to have knocked out 13 tanks and killed several dozen soldiers single-handedly after his comrades were killed. How much of ths description is true is hard to tell credit to this story is given by the fact that Christen was awarded the Iron Cross and Knights Cross simultaneously which is very rare and brings us to a problem:
I have read most Medal of Honor citiations for World War 2 and a major difference between the MoH and the Knights Cross is that the Knights Cross was more often than not awarded when a Soldier already had the Iron Cross et cetera this made it rare that enlisted men got awarded the Knights Cross. The attention given to a Iron Cross recipient is rather limited and therefore many of such actions were forgotten. Another factor is that the Wehrmacht was in constant retreat and most of these "one man army" moment were likely soldiers who were killed or captured after, either way there was nobody to recommend them for an award. Another problem is that if they survived the war nobody cared what they did in WW2 especially if they lived in the GDR. If you are interested in displays of heroic actions on the Allied side just go through the Medal of Honors and you will find plenty.
It's kind of a mess. For Germany, the Wehrmacht and SS were often at odds, much of which dealt with After-Action Reports. The SS wanted lots of heroes, so they'd either straight-up fabricate reports, or lend all kills in the unit to a single commander. It became unofficial Wehrmacht doctrine to pretty much halve any damage reports by the SS when taking reports into consideration.
Air Force reports on all sides are an absolute mess no matter the nation. It's hard to claim ground kills when you can barely see what type of vehicle/troop it is, and verify if your attack killed it (and then even temporarily or permanently). So you'll end up with these unbelievable stories of pilots wiping out columns of tanks, when the other side is claiming the lost of trucks and light armored vehicles. The surveyors would often lend to this, as they'd get get to a battlefield late, and if they couldn't determine what knocked out a vehicle, would chalk it up to an air force kill. Mortain is a famous example, with discrepancies of around 100+ vehicle kills wrongly attributed to Allied air attack. Reports of air-to-air kills seem to mostly be reliable, though.
Then there's just plain not-knowing. If you shoot a soldier at long range, then you'll assume he's dead. So you'll see Hero from Country A claim 40 kills. Country B claims only 5 soldiers dead, but 30+ wounded or missing. Not necessarily lying, but it's one of those things to keep in mind.
I apologize as it's not much of an answer, but things to consider before you jump into the brown sea of internet WW2 discussion (especially of the Axis). It mostly goes to show that the "one man army" stories are usually fake or incredibly over-exaggerated. For example, the most verified stories of soldiers like Levaslaiho, Murphy, Kurt Knispel, etc. were usually because they worked as part of their units, so achieved great feats that are verified by other records in the unit.
OP: there are various Wehrmacht and SS names that are associated with spectacular feats of arms and enormous kill-counts, but extreme caution should be used in dealing with them. The SS in particular were desperate for heroes to make them stand out next to the - bluntly, much better - Heer. This was also true after the war, where SS memorists tried to create a 'Lost Cause of the Third Reich' by talking up their own exploits and keeping much of the surviving documentation in their own private possession, as well as co-ordinating the message with groups like the HiAG. A worked example of Nazi fibbing is shown here. Note that the Germans were not above lying in their own internal reports.
Wehrmacht 'one man armies' are perhaps closer to reality in their exploits. Names that can't go unmentioned would be:
Otto Carius and Kurt Knispel: the second and first most prolific tank aces of the German Army and possibly the war. However, Carius himself admitted that their kill-counts were inflated by around a third for propaganda.
Hugo Primozic and Franz von Malachowski, assault gun aces.
Josef Allerberger, Matthaues Hettzenauer, Friedrich Pein, and Bruno Sutkus, snipers.
Erich Hartmann, Adolf Galland, fighter aces.
Hans-Ulrich Rudel, Stuka pilot.
Otto Kretschmer, U-boat ace, nicknamed 'The Tonnage King'.
Almost all these kill counts will be significantly inflated, both by soldiers' natural overestimation and by Nazi propaganda. There are also some other factors to consider - for instance, the Luftwaffe regarded a handful of kills on the Western front as better than big numbers in the East, as British and American pilots were considered better foes. German soldiers in Stalingrad considered a silver infantry assault badge to be worth more than the iron cross. Be aware if you research this topic that popular writing on the Nazi war machine is awash with bullshit and far-right crap. A discerning eye is vital.
Off the top of my head there are Katou Tateo and Funasaka Hiroshi from Japan.
Katou was a pilot who lead the 64th Squadron, nicknamed the Katou Hayabusa Squadron. He and his squadron were one of the most highly decorated groups in the Japanese military, with hundreds of aerial victories under their belt, and Katou himself having at least 18 personally.
Funasaka Hiroshi on the other hand was an infantryman. At the Battle of Angaur he is said to have personally killed over 200 allied soldiers. By the time the medics finally got to him, he was so wounded they gave him a grenade to end his suffering and left him to die. However he continued to fight, gaining so many life threatening wounds that his fellow soldiers thought he was immortal. In one engagement he took down 3 American soldiers with 3 bullets from his pistol in rapid succession. In another he killed one American soldier with a bayonet, and then threw it another American soldier, impaling it in his jaw. But even he had his limits, and when he noticed that his wounds had become infested with maggots, decided that he would end his life, and try to take the American commander down with him. Strapping six grenades to his body and carrying a pistol, and snuck into the American camp. By this point he had more than 24 wounds, including major lacerations on his left leg, two gum shot wounds on his left arm, a bullet in his stomach, a sprained right shoulder, a dislocated right foot, and blunt force trauma to the head. He also had burns all over his body, and more than 20 shrapnel wounds. He was shot in the jaw when he tried to make his attack, and the American medical who saw him didn't expect him to survive. But 3 days later he was back on his feet, and few days after that attempted to make his escape, setting fire to the base's explosives depot in the process.