under known composers

I will never stop singing the praises of Peter Mills. Easily the best lyricist working today.

Adam Wachter's musical Tarrytown is also really great (most people know him as the music director on Disney Plus's Encore).

This is a tricky question since under known is relative, but Billy Recce and Preston Allen come to mind. I don't know where Shaina Taub falls on the spectrum, as to me she feels well-known (and will be once Devil Wears Prada comes to Broadway, she will be). Also, Kyle Jarrow! (again, he feels known to me, but I think a lot of people wouldn't think of him as a "name".