The usual dates given for the onset of his complete deafness are typically 1814-1815.
So, for his last 13ish years until his death in 1827, he was likely no longer (audibly)hearing the following great works:
Piano sonata in E minor (Op.90)
Cello sonatas (Op. 102)
Piano sonata in A (Op. 101)
Piano sonata in Bb “Hammerklavier” (Op. 106)
Piano sonata in E (Op. 109)
Piano sonata in Ab (Op. 110)
Piano sonata in C minor (Op. 111)
33 variations in C on waltz by Diabelli (Op. 120)
“Missa Solemnis” in D (Op. 123)
Symphony no. 9 in D minor (Op. 125)
String quartet in Eb (Op. 127)
String quartet in A minor (Op. 132)
String quartet in Bb (Op. 130)
“Grosse fugue” for string quartet (Op. 133)
String quartet in C# minor (Op. 131)
String quartet in F (Op. 135)
Amazing output; incredible, unique pieces!
This certainly gives a different spin, understanding, and appreciation when hearing the above works. We can safely say that Beethoven was writing purely, then, from his oral imagination, memory, and past experience. I believe he was deeply, intuitively, and instinctually writing Keats’ “ditties of no [audible] tone”–the music of his soul and spirit. He was writing that music that remained deep inside him. And he was writing the music that he really wanted to compose as in the case of his mass. In that, I believe he wrote both the misery and suffering of the human condition in the opening two sections and later concluded with the hopeful possibilities typically interpreted in and by the positive ending. Despite his previous suicide attempts and pessimism, Beethoven hoped for a higher state and salvation for humans. Unlike no other genius-composer, his work, attitudes, and approaches are a perfect balance of positive and negative, hope and pessimism, the ideal and the real.