Mozart
Fantasy in D minor, K. 397
I have rarely performed Mozart’s d minor Fantasy, but have taught it countless times. D minor is a special key for Mozart. One only need think of Don Giovanni, The 20th Piano Concerto, and the Requiem, his final work, to get a sense of the gloom that Mozart associated with the key. 
Beethoven
Sonata in G Major, Op. 49, #2
   1.   Allegro ma non troppo
   2.   Tempo di Menuetto
Sonata Opus 49 #2 has long been a favourite teaching piece of mine. There are fewer technical difficulties in it than any of Beethoven's 31 other works in the form. It 
was possibly written around 1795, when he was only 25 years old, but because it was not published in Vienna until 1805, nearly a decade after it was actually written, it was assigned then-current opus and sonata numbers, which classified it alongside works from the composer's “middle”period.