I have personally harvested only a few, maybe 3 or 4 total, that have probably weighed over 200 pounds field dressed. One of them may have weighed over, or at least right around, 250 on-the-hoof, but I can't say for certain because I've never weighed any.
I've heard legendary stories about 400 pound bucks before, but have never seen seen any in person. In, (I believe 2008), a guy in my shotgun party did harvest the only deer that I'd honestly say weighed at or over 300 pounds field dressed, and well over 300 on-the-hoof. That thing looked like a damn donkey with a set of huge, thick 50 pound antlers with stickers and kickers all over the place. I wouldn't have believed it if I wouldn't have seen it with my own eyes and helped load it into my truck. When field dressing it, my buddy rolled his HUGE stomach out onto the ground. We could already tell what it was full of, as tightly as the membrane was stretched, but out of curiosity, his son cut into it with his knife. It was like a water balloon popping in slow motion. There was enough corn in there to probably fill a 5 gallon bucket. This buck was an absolute hog.
For what it's worth, many moons ago, I wrestled heavy-weight in HS and did some mixed martial arts in my 20's & 30's against some big-ol-boys, so I've got some real life experience to reference when it comes to picking up and moving around big heavy bodies.