The works of Johann Sebastian Bach and some of his sons are extensively studied and performed, however their relatives from the previous generations often remain out of the spotlight. Professional musicians in the Bach family can be traced back to at least Bach’s great grandfather Johannes (Hans) Bach known as ‘der Spielmann’ (the player). The Altbachisches Archiv (the old-Bachian archive) is a collection of vocal music written by some of the older generation members of the Bach family.
Here is the motet 'Lieber Herr Gott, wecke uns auf' composed by Johann Christoph Bach, the first cousin of J. S. Bach’s father, and performed here by the Cantus Cölln choir, Concerto Palatino and Konrad Junghänel. https://youtu.be/TA0tz1A6n9k
Here is the aria 'Ach, wie sehnlich wart ich der Zeit' by Johann Michael Bach, the first cousin once removed and father-in-law of J. S. Bach. https://youtu.be/TNLhupTEGj4

Some sources for further reading:
- Grove article on the Bach Family https://doi.org/10.1093/gmo/9781561592630.article.40023
- Rose, Stephen. "The Altbachisches Archiv." Early Music 33, no. 1 (2005): 141-144. https://www.muse.jhu.edu/article/181850.