9 symphonies.
32 piano sonatas.
Someone add the other stuff he wrote. Definitely more than "10 things."
Beethoven wrote 20 Quartets!
Lieder was a German song. Beethoven composed many lieder for the piano.
Beethoven wrote nine symphonies. Is this what you intended to ask? Beethoven wrote nine symphonies. Is this what you intended to ask?
Beethoven wrote 38 to be exact! Though the last 6 didn't have opus. Have a look at 'How many piano sonatas did Beethoven wrote'. There are some extra details about this question.
Beethoven wrote many pieces of music, lots of them are famous.
he composed about 80n songs
BeeTHoven composed one opera, Fidelio. It is sometimes considered that he wrote two, the first version of Fidelio being a full-score opera entitled Leonore.
He composed for 22 instruments, mostly piano and violin
I'm sure that Beethoven wrote many postcards, and I'm not sure if I know of any famous postcards, by Beethoven or anyone else.
The famous deaf composer Beethoven composed many beautiful pieces.Perhaps the most famous of these is Fur Elise which can be recognized by the name or tune by many people.
9 symphonies
Beethoven wrote many works, and many of them are famous to all classical music lovers. The Moonlight Sonata, Op. 27, no. 2 and the piano piece "Fur Elise" are candidates, as are the opening movement of the 5th Symphony and the "Ode to Joy" from the 9th Symphony. It would be hard to narrow the choice among those four.