In addition to the Jews of Europe, many millions (I don't quote a number because it varies from source to source) of non Jews were specifically targeted by Hitler and the Nazis.
The first target were the people of Poland; "All Poles will disappear from the world.... It is essential that the great German people should consider it as its major task to destroy all Poles." Heinrich Himmler
The next group were Jehovah Witnesses who were forced to wear purple armbands and thousands were imprisoned as dangerous traitors because they refused to take a pledge of loyalty to the Third Reich.
The Gypsies of Europe were historically treated the same as Jews. The Nazis believed both the Jews and the Gypsies were racially inferior and degenerate and therefore worthless. Their extermination was a parallel operation carried out using the same process as the extermination of the Jews.
All Europeans suspected of being a part of or supporting the underground and all conscientious objectors were targeted for death (no questions asked). Even though most German citizens were supportive of Hitler's plan to control Europe, there were German citizens who died because they refused to go along with Hitler's plan.
Pastors, priests, and clergymen were high priority targets. Hitler expected his followers to worship the Nazi ideology. Catholic priests and Christian pastors were often influential leaders in their community; they were sought out by the Nazis for transport to camps.
Homosexuals and those suspected of being homosexual were sent to the camps. Even SS soldiers who were suspected were sent to the camps wearing their SS uniforms with the pink triangle sewn on it. This was done to ensure they receive the worst treatment in the camps.
The Nazi regime decided early that it was a waste of money to support those who could needed care, so the disabled and mentally ill were disposed of. Even members of good Aryan families were destroyed without their families being informed; families would receive a notification from the institution saying that their relative had died of a disease and cremated. In reality, these people had been loaded into transport trucks with the exhaust line fed into the cargo area so all they needed to do was drive them to a disposal site. Later, a propaganda agenda was launched throughout Germany to convince the public that euthanasia was the humane course.
During World War I, black African soldiers were recruited by the French during the Allied occupation. Some of these black soldiers married white German women that bore children referred to as "Rhineland Bastards". In Mein Kampf, Hitler said he would rid Germany all the children born of African-German descent.
The non Jewish spouses of German Jews were were forced to choose between divorce or concentration camps. Of course any mixed children would stay with the Jewish parent. Any of these non Jewish spouses who chose their family were sent to the camps.
Many other groups of varying types were also targeted. People who enjoyed or supported in any way, non-German, Nazified arts were considered degenerates. American jazz, impressionist art, and any science that didn't support the superiority of the Aryan race, just to name a few.