As I understand it, all the versions have the same meaning. Which one is the friendliest? Is there any other nuances which sentence to use in practice? Maybe, the first one is old-fashioned, if it's used in Shakespeare's works. For me, they are completely the same, but with different words.
There is no more to say.
There is nothing else to say.
There is nothing to say anymore.
There is nothing left to say.
Best Answer
There's nothing outdated about the first option (the famous Shakespearean equivalent is Hamlet's last line, "The rest is silence.")
All these could be a bit cold, as noted, because they suggest ending communication, as in "I have nothing to say to that man" (meaning "I might say much, but I'm not talking to him"). Context could soften them, but without any, all of them seem to convey "There will be no need for any more communication between us," and could be used when communication has broken down.
A casual, chatty way of simply saying that the current discussion has met its needs might be "Well, I think we've covered everything." Even more genuinely polite might be to make sure the other party is also finished: "That's it for me; is there anything else you want to cover?"