You have a good start. Here are some I missed from your repertory:
Baroque:
Scarlatti sonatas (see here for some specific suggestions:
https://www.pianoforum.net/cgi-bin/yabb/YaBB.cgi?board=repo;action=display;num=1077145772)
Handel: He is not my favourite keyboard composer, but the suites are very nice.
J.S.Bach: The six partitas and if you are ambitious, why not the Goldberg variations?
Couperin: Although purists demand him to be played on the harpsichord, the new CD by Angela Hewitt shows the folly of the traditionalists. (I particularly like “Les Barricades Misterieux”)
Classical:
Haydn - sonatas (the late ones are very advanced and wonderful)
C.P.E.Bach (some great sonatas, unjustly underplayed).
Clementi: Unjustly forgotten by grown up pianists, I like his sonatas better than Mozart’s (and so did Beethoven).
Romantic:
Mendelssohn (Songs without words, Variations serieuses, Capriccios, etc.)
Schubert (I particularly love the Impromptus)
Schumann (Everything he wrote is top quality)
Grieg (Lyric pieces, I love the Holberg suite, and naturally the concerto)
Rachmaninoff (no Rach?)
Modern:
More Prokofiev (see here for some not too advanced suggestions:
https://www.pianoforum.net/cgi-bin/yabb/YaBB.cgi?board=stud;action=display;num=1077907916 – If you want advanced go for the sonatas – and if you are feeling fearless why not the concerts?)
Shostakovich (see here for some ideas:
https://www.pianoforum.net/cgi-bin/yabb/YaBB.cgi?board=repo;action=display;num=1073648526 – his concerto no.2 is not exactly easy, but it is one of the easiest concerts).
You can get a few more ideas for modern composers here:
https://www.pianoforum.net/cgi-bin/yabb/YaBB.cgi?board=repo;action=display;num=1077625353These are just mainstream composers – standard repertory. If you want the obscure ones (and I would encourage you to get out of the well-trodden path) then the list is almost endless.
Best wishes,
Bernhard.