On 17 September 1824, Beethoven wrote to the sons of Bernhard Schott. (The sons ran the music-publishing firm that their father founded in 1770 and which still exists 250 years later.) Beethoven promised delivering a string quartet to them by October and then added:
As I have far too much work to cope with and as my health is poor, people must just be a little patient with me; I am staying at Baden on account of my health or, rather, on account of my ill health. But I am feeling better already. Apollo and the Muses are not going to let me be handed over to Death, for I still owe them so much; and before my departure to the Elysian fields I must leave behind me what the Eternal Spirit has infused into my world and bids me complete. Why, I feel as if I had hardly composed more than a few notes. I wish you every success in your efforts on behalf of art. For after all, only art and science give us intimations and hopes of a higher life. (Beethoven Letters No. 1308)
Beethoven had first mentioned a string quartet to Schott on 10 March 1824, but it wasn’t ready by October as he promised.
Or November, or December, or January …
Anton Diabelli wasn’t the only music publisher soliciting piano pieces from multiple composers (Day 334). Carl Friedrich Müller (a former actor who had become disabled) wanted short and light piano pieces that he could publish as collections.
In response to Carl Friedrich Müller’s solicitation, Beethoven contributed a waltz in E♭ major in November 1824. This piece is catalogued as WoO 84, and it has the structure of a classical Minuet with a contrasting Trio section.
Beethoven’s autograph of the WoO 84 waltz is on the second page of this treasure on the Beethoven-Haus site, but the manuscript is missing the Trio section.
[beethoven.de/en/media/view/…]
The 4th and 5th pages contain pieces Beethoven wrote for Müller a year later.
Here’s Müller’s Musikalisches Angebinde zum Neuen Jahre (Musical Gift for the New Year) containing 40 “new waltzes” from mostly obscure composers but a few recognizable ones. It's alphabetical by composer, so Beethoven’s contribution is first:
#Beethoven250 Day 339
Waltz in E♭ Major for Piano (WoO 84), 1824
This piece is popular among young pianists.