this anime has already been said but i don't ca- HUNTER X HUNTER!!!! hunter hunter is very dark and intense but i highly recommend it its my all time fave anime the creator is a genuious there no overly long boring arks not much fan service :( no annoying tunsderes (the world doesn't need tunsderes) also here is some others i highly recommend dragon ball (the original) one punch man ultimate oktau teacher
stay away from sao, sao is overrated edit 1: honestly it depends on what genre you're in to. Assassination Classroom is pretty damn good (no its not a serious anime), The Familiar of Zero is also amazing, and is 4 seasons long.
If you're in for the long run then I would say fairy tail.. It's a really long adventure kinda anime. (Personally I love it) Akame ga Kill is a personal favorite too
what about lazytown? lazytown is the best anime or cory in the house or spongebob. those are some other animes to watch