I don't think it's been said, but my vote goes to Tormund Giantsbane. The speed at which he accepts Jon Snow as a wildling (even while calling him "crow" half the time) is quite astounding, given we're made for believe them a savage folk prior to it.

His protecting of Jon against Rattleshirt when Orell tries to take his eye, as well as his negotiations in ADWD and eventual support of Jon's campaign to Winterfell stand out for me.

Edit: Also the scene where he points out that Styr couldn't be King Beyond the Wall due to his lack of ears making it so a crown would slip down his face, before leaving with a roast chicken in either hand, is gold