Vaughan-Williams Fantasy on Greensleeves, excerpts from Faure’s Pelleas et Melisande come to mind. The parts on the AHS list seem quite difficult.
Procession of the Nobles by Rimsky-Korsakov is available with a straight-forward harp part. It depends on how good your students are at counting and rhythms. Wagner’s Prelude to der Meistersinger is almost all chords.