You get lots of passagework in the Mozart sonatas, it's not super advanced but at the same time it requires a lot of refinement and mastery to play really well. At the same time, Mozart is not really vapid "show-off" music. Does that seem to suit your purposes?
Bach is also good for general technique development. Anything fast from the Well Tempered Clavier will be good for you. Try the D major prelude from book 1 if you want a challenge. C sharp major, G major and F sharp minor are good too.