This is a violin piece that touches a lot of people
Pure Music
Rose of the South Round Dance, Tales of the Viennese Woods Round Dance, The Artist's Career Round Dance, Viennese Temperament Round Dance, The Blue Danube Round Dance, The Emperor Round Dance, The Sound of Spring Waltzes
Besides the Strauss family's, there are a few good ones:
Wald Retreat Fell: Waltz from Gold and Silver, Waltz from Ice Skating
Rosas: Waltz from Ride the Waves
As for the piano:
Chopin: Polish Dance No. 7 (Heroic), Nocturne, Puppy Waltz
Beethoven: "Passion Sonata," "Moonlight Sonata," "Pathétique Sonata," "To Alice"
As for the erhu: Erquan Yingyue, Spring River and Moonlit Night, Idle Habitat Song, Bright Line, Han Palace and Autumn Moon, Good Night, Racehorse, Sanmenxia Fantasy, Yu Bei Narrative, Orchid Blossom Narrative, the First Erhu Rhapsody, and Sunshine on the Tashkurgan.