Any ballad in which members of the same family unwittingly or accidentally kill each other.
Babylon Child 14 Brother kills 2 sisters and is told by third sister who she is. He kills himself.
Cruel Brother Child 11 Brother accidentally kills brother with his dagger while they are wrestling. Brother kills himself.

Cruel Mother is certainly sad and shocking but was probably written by a broadside hack as a warning to young well-heeled girls to avoid liaisons with servants. The probably very young girl of the 17thc is definitely distracted when she does the dastardly deed. Such deeds were not unheard of until quite recently now the stigma attached to bastardy is not so draconian.