Some keys:
C Major: this is the key that the American National Anthem is in
G Major, the key Coffin Dance is in
Ab Major, one of, if not the most heroic keys there is (Chopin's Heroic Polonaise is in this key)
C# Minor, usually thought of as the spookiest key
D Major, which I'm pretty sure Megalovania is in
If you guys have any other ideas for keys, let me know, but just make sure it's a major or minor key, I don't want to deal with Lydian or Dorian or stuff like that