I’ll give you a list of “classical hits”, I hope that when you listen to them, you’ll try to listen to more things. There are hundreds of years of the best music for you to find. A couple of favourites:
Mussorgski: Promenade, Baba Yaga hut’s, The great gate of kiev, A night on the bare mountain.-
TChaikovsky: Most of Nutcracker, 1812 overture, specially the ending, Slav March, the first bit of his Piano Concerto. If you want to listen to music you’ll instantly recognize, this is your composer.-
Manuel de Falla: Pantomima and Ritual Dance fire from “El Amor Brujo”.-
Chopin: All his piano pieces are famous. Polonesa N°6 is a hit.-
Gershwin: An American in Paris and Rhapsody in blue.-
Sibelius: Vals Triste and Finland.-
Bizet: His Carmen Suite is and will always be famous.
Beethoven: His Romances for Violin and Orquestra, the 1st movement of his 6 symphony, For Elise, Moonlight sonata.-
Debussy: Moonlight Sonata, Arabic N° 1 and 2, prelude to the nap? of a faun.