The sci-fis of Iain M. Banks; Consider Phlebas, The Player of Games, Use of Weapons, The State of the Art, Excession, Inversions, Look to Windward, Matter, Surface Detail (These are all part of the Culture series). Then the rest of his novels that are not playing in the Culture universe... Against a Dark Background, The Algebraist and Feersum Endjinn. Only this last one, Feersum Endjinn plays in the far future Earth. All the others has a different culture, different creatures, different universe. Some of the novels has cross reference with humans or have human characters, such as Against a Dark Background. But as I recall all Culture novels fits to your criteria and they're really good novels with twisted, good stories, detailed worlds and memorable characters (Banks and his works are one of my favorites.).
Or if you want easier ones, yet quality sci-fi... Harry Harrison's Deathworld trilogy. There, only the MC is a real human. The rest of the characters, while they're also humans, they're from different planets and have different traits. Deathworld 2 and 3 also plays on different planets, in different alien civilizations.