[@NekoMizu] I suggest you do some research on google about what people are discussing here. Particularly Steampunk and the stuff Aix was talking about. you don't need to read the entire wiki page, but it'll help you understand what a genre is. Steampunk is most certainly not future anything though, despite having technology that has never and will never be invented.

You also need to state what "the way you are thinking of" representing a "modern/future/past" world is. I've seen post-apocalyptic settings where it's the future, but due to resource shortages people rely on modern and old technology. Is that what you're talking about?