From what I can remember, Steins Gate and Noragami don't have ecchi to the point its a minor focus or explicitly, most of them might feature very mild fan service (eg. Steins Gate had a bath scene but barely showed much, there was also one specific angle-shot of Kurisu bending over a table, but nothing memorable otherwise. Noragami I don't think had many ecchi moments, but Bishamon does wear a black bra or something in combat) .
I can't myself remember Classroom of the Elite well enough to say, but I do know there was one attempted rape scene in an episode.
