This gentleman knows so much about the history of keyboard instruments! The whole 2-part video is very interesting. He demonstrates the clavichord at 2:45 and the harpsichord at 6:12, and in the second video he demonstrate the early piano at 2:17 and the modern piano at 6:40.
Here is one of Bach's songs played on a baroque instrument called the "archlute" which is very similar to a "theorbo," which you can see in some of the videos on the Telemann page.
Recorders have been used in music for a very long time and they come in many different sizes. Here is one of Bach's pieces played on the recorder.
This is an interesting video about an old instrument called the hurdy-gurdy.