What 18th century piano pieces are there?

Shakespeare was from the late 16th/early 17th century, which is before the piano was even invented (which was around 1700). This doesn't mean that you cannot play keyboard music from Shakespeare's time; only that it will not be music written FOR the piano. I think you should look-out for a copy of the 'Fitzwilliam Virginal Book'. The 'virginals' was an early keyboard instrument very popular in Shakespeare's time and resembles (and sounds like) a small harpsichord.

The 'Fitzwilliam Virginal Book' is a compilation of keyboard music from exactly the time that Shakespeare was alive and includes music by composers of the time such John Bull, William Byrd (who wrote a LOT of such music), Giles Farnaby, Orlando Gibbons, Thomas Tompkins and Jan Pieterszoon Sweelinck. A great deal of the music is quite straightforaward to play and very attractive and so this would be my recommendation to you.

Ok, there is a confusion about the periods of time. Shakespeare lived between 16-17th century. Either you want Shakespearan time of music or 18th century music, but not both at the same time.

If you want 18th century piano music, early piano works of Beethoven, the entire piano works of Mozart and Haydn are 18th century music, such as their piano sonatas.

If you want Shakespearan period music, there was none written for piano at the time. If keyboard music is closer for you to use, then you can find either organ or harpsichord music in early Baroque. For example, Johann Pachelbel's liturgical organ music and Johann Kaspar Kerll's Battaglia.

The late Renaissance even did not have any keyboard music written (Shakespeare time was between late renaissance and early Baroque).

Looks like the best ones for your piano performance level are probably from the Anna Magdalena Bach manuscripts, which will lead you to composer J.S. Bach.

J.S. Bach lived nearly in the time of Shakespeare. So the best bets for J.S. Bach at that point from the Anna Magdalena Bach notebook are the

1. Minuet in G

2. Musette in D major

Also look at the 10 Little Preludes by J.S. Bach.

Hope all of this helps.

NONE!