I imagine there is no comprehensive listing of such choices. Though I am skeptical as to whether these choices actually change the response of npc. Don't get me wrong I appreciate the chance to chime in once in a while and it's not like the Final Fantasy single player games ever actually granted players extensive dialogue choices.

Though this mmo is so long and winding that any individual effort to map out such choices would likely be hampered by time restraints. Off the top of my head, I don't think I have seen more than 5 such instances where I actually made this choice. Maybe it is just there for flavor and as a pause between long speeches?