strongest F smash in knockback is DeDeDes, 2nd is Ikes
Snakes is up there, among some others
note to self - finish marth vs everyone F smash and Up Smash on center of FD list
another note to self - up/down from marths up smash will be Vertical Resistance or Vertical Weight, and for Horizontal it will be just called Weight
(Vertical is a combination of Weight + Fall speed, as it was in SSBM, HOWEVER, in Brawl weight is a much bigger factor to upwards KOs than Melee was. Samus in SSBM (dies off top fast, but still lives long upwards in Brawl) is good proof of this.
Bowsers the TRUE heaviest (left right) in just pure weight, while DeDeDe has the most upwards resistance, but if you combine it with DDDs great recovery due to 5 jumps, I think DeDeDe has the most "Endurance", which is how long he lives overall, which is too hard to rank properly in a stat list so I can't make one for that, but I can make the other two lists using Marths F smash and Marths Up Smash. I will also make a falling and fast fall falling speed list. I'll do it tomorrow most likely.
for now tho, im going to bed
edit - i just realized why falling speed matters less for living long in Brawl than it does in Melee, because you fall so slow in Brawl it's less of a factor, and WEIGHT is what determines how hard you get hit (and is the ONLY factor in determining how hard you are hit horizontally, and would be the same thing for vertical except that falling speed is taken into consideration, so falling speed has 3 factors: weight, falling speed, and falling speed acceleration).