No. 1: Carl Yastrzemski, 1967
It had to be Yaz. It had to be the Triple Crown year. It had to be Yaz leading "The Impossible Dream" team. It feels nice to be able to get Yaz more recognition after I left him on the bench for the all-time WAR lineup, and this season was almost always going to end up being the best.
Yastrzemski collected 12.4 WAR in 1967, which is given the distinction of the greatest position player season of all-time, non-Babe Ruth division. A singular season that held its own in history, being the last Triple Crown until Miguel Cabrera in 2012. I don't know what else Yaz needed to do in this season, but his OPS+ for the year sits at 193 (I would've assumed it would end up in the 200s), but besides this one number, there's no holes in the resume. It's the greatest season put together by a single Boston Red Sox player, and I don't think that it's going to be beat any time soon.