We have now worked through:
Beethoven's 32 piano sonatas
Mozart's 18 piano sonatas
Tchaikovsky's Seasons [all 12 of them ...]
Mussorgsky's Pictures from an Exhibition
Bach's Inventions and Sinfonias
Bach's English and French Suites
And I am now playing through Haydn's Sonatas and Bach's Well-Tempered Clavier volume 1. The early Haydn Sonatas are not as well-known and are much easier than Mozart and Beethoven's: more like their sonatinas, but maybe easier still for the first few in volume 1 of the Henle edition. Bach's WTC vol 1 is still a challenge, though I have played through them before.
This is a sight-reading exercise, by the way: not at all polished performing!