Stories catch heroes like honey catches flies. With all the varieties of stories, we have evolved simultaneously many different types of heroes and heroines. In the most general sense, a hero is a protagonist, that is the (or a) main character with whom the audience identifies and who is in conflict with the antagonist (or villain). In its original Greek usage, a classical hero was semi-divine human (in other words, a demi-god), such as Heracles, Theseus, or Perseus. Even the Greeks weren't satisfied with the classical hero alone and quickly followed him up with the tragic hero. If you think adding anti-hero to the list and calling it a day covers the field, you haven't sunk nearly enough time into thinking about the field of heroism. Start in the shallow end with the introductory articles in Wikipedia and in TVTropes, and then get ready to lose hours of the day and maybe even some of your comfortable hours of sleep for starters, for you've skipped over many kinds of heroes, only to land in anti-hero land which also has a diverse population of types, and have a lot of catching up to do.
Once you have of populated a goodly list of hero types, then you can ask questions about the necessary structures and elements that have been proposed by modern theorists from Carlyle to Raglan to Propp to Campbell. So much for simple courageous self-sacrifice for the good of others in the struggle against evil! As long as human nature and our understandings of good and evil remain complex and placed in diverse contexts, we are likely to continue to tell complicated stories of heroes that develop the options for heroism in ever more baroque patterns.