Beethoven
Sonatas 1-32
33 Variations on a Waltz by Anton Diabelli
11 Bagatelles, Opus 119
6 Bagatelles, Opus 126
15 Variations & fugue on a theme from Prometheus in E flat (Eroica variations)
Except for the Concertos and some other pieces, most of
Chopin's works are solo piano.
Ballades No. 1-4
Nocturnes No. 1-21
Mazurkas No. 1-59
Polonaises No. 1-18
Etudes No. 1-24
Piano Sonatas No. 1-3
24 Preludes
19 Waltzes
etc, etc, etc....
Rachmaninov's solo pieces:
Sonatas 1 & 2
Prelude in C sharp Minor
8 Etudes-tableaux
10 Preludes
13 Preludes
9 Etudes-tableaux
Variations on a theme by Corelli
I will have to get back to you with more, but that should last you a good deal.
Also, those already mentioned above.