Bach wrote keyboard sonatas, symphonies, oratorios, liturgical choir pieces and motets, operas and songs. Because of Count Wilhelm's predilection for Italian music, Bach had to adapt his style accordingly, but he retained stylistic traits of the music of his father and of his brother, C. P. E. Bach.
Its hard to keep the Bach family apart at times because there were so many of them with similar names. J.C.F. Bach is one of the not-so-famous ones. You may not have heard any of this Bach's symphonies.