Lara, Andrade or Golovkin. Khan would give him problems due to his speed, but he lacks the discipline to stick to a game plan. Thurman is a tad too green. Brook wouldn't land a glove on Floyd due to his style. Garcia wouldn't win a single round. Bradley on his very best day would give him kittens, but probably get robbed on the cards.
Nobody. I've seen maybe 100 of these threads worded in different ways and the results remain the same. Nobody will beat him right now. If he keeps fighting like weak ass Bernard Hopkins though, it's only a matter of time before somebody beats the breaks off his ass.
Who cares, he never fights who we want him to fight. Imagine your favorite football team refused to play another team for years when they were on top, and then decided to play them when they were on the slide at the end of their time. That's what Floyd has done for the best part of a decade, fools like you OP eat it up.
Khan could beat him, but he's not disciplined enough to stick to the required game-plan. Floyd has rarely muttered Bradley's name. He knows he'd cause him all sorts of problems.
Bradley wouldn't cause him problems. Floyd would have the longer reach, would be taller, and he's the smarter fighter of the two.
Would Bradley have the best chance? Bradley's not exactly hard to hit. Floyd would hit him all night.