This may sound weird - or not - but what my long time players want most are two things:
A detailed, lovingly done Rooftop Inn, because in our games, like some sort of in game joke, it always started and ended there, and it probably always would

With one notable exception which ended at the...
The Library of the Magical and Mundane. We had a very interesting things happening there, a map of the maze under it would also be cool.
The sewers... oh I wish we could insert some of the places we invented down there lol