Civilian attacks similar to or like The Holocaust

The effort by Nazi Germany and its World War II allies to commit ethnic cleansing and eventually genocide against Europe's Romani people during the Holocaust era. Issued on 26 November 1935, classifying the Romani as "enemies of the race-based state", thereby placing them in the same category as the Jews. Wikipedia

The systematic persecution of Serbs which was committed during World War II by the fascist Ustaše regime in the Nazi German puppet state known as the Independent State of Croatia (Nezavisna Država Hrvatska, NDH) between 1941 and 1945. Carried out through executions in death camps, as well as through mass murder, ethnic cleansing, deportations, forced conversions, and war rape. Wikipedia

During World War II, Nazi Germany engaged in a policy of deliberate maltreatment of Soviet prisoners of war (POWs), in contrast to their treatment of British and American POWs. Grounded in Nazi racial theory, which depicted Slavs as sub-humans . Wikipedia

Pogrom against Jews carried out by SA paramilitary forces and civilians throughout Nazi Germany on 9–10 November 1938. The German authorities looked on without intervening. Wikipedia

Massive Nazi German operation consisting of the forced resettlement of over 1.7 million Poles from all territories of occupied Poland with the aim of their geopolitical Germanization between 1939 and 1944. The expulsions were justified by Nazi racial doctrine, which depicted Poles and other Slavs as racially inferior Untermenschen. Wikipedia

Nazi German operation aimed at the eradication of the Polish intelligentsia in Pomeranian Voivodeship and the surrounding areas at the beginning of World War II. Part of a larger genocidal Intelligenzaktion, that took place across most of Nazi-occupied western Poland in the course of Operation Tannenberg , purposed to install Nazi officials from Sipo, Kripo, Gestapo and SD at the helm of a new administrative machine. Wikipedia