I think the answer to this question could be Crosby, if the question is defined in a very specific/favourable way.
Suppose Crosby played 55 more games (5.0% of his career total) - 36 games in 2011, 12 games in 2013, and 7 games in 2015. It's very likely that he wins three more Art Ross trophies. You'd have to think he'd also get the Hart in 2011 and 2013 (maybe not in 2015 due to voter fatigue and what would likely be a narrow margin of victory). He already won the Lindsay in 2013, but he almost certainly would have won it in 2011. So, that's six major trophies, based on only 5.0% of his games.
I can't think of any other player who would gain so much hardware for such a small percentage of their games. (Lemieux, Orr, Neely, Bure - they come close, but I can't "find" six trophies for any of them, with 5% more games played). But I think this is a flawed argument for three reasons:
First, it's based on looking at trophy counts only, without considering any context. Yes, Crosby's legacy would be stronger with the Hart and Art Ross in 2013. But the gap between that outcome, and what actually happened (Hart runner-up, 3rd in scoring, Pearson trophy), isn't huge. And even half-seasons (like Crosby's 2011 campaign) clearly have some value for a player's legacy (see Lemieux's 2001, Neely's 1994, Forsberg's 2004, etc). I know some people push the narrative that trophies are binary (you either win it or you don't), but I think that's a shallow way of thinking.
Second, I'm skeptical about changing some parts of Crosby's career, and assuming that everything else stays the same. A huge part of his legacy is winning back-to-back Conn Smythes, ranking 5th all-time in playoff scoring (behind only four members of the Oilers dynasty), being leading scorer and MVP at the 2016 World Cup of Hockey, and having four top-four Hart finishes from 2016 onwards. Maybe if Crosby had already won, say, five Art Ross trophies and four Hart trophies by age 27, he wouldn't have pushed himself so hard in the playoffs, or at the WC tournament, or in some of his later seasons. And it's not obvious to me that Crosby, with 5 Art Ross trophies and 4 Hart trophies, but without all those other accomplishments I just mentioned, is necessarily a better player all-time. (The counter-argument is Crosby is driven, and seems to live and breathe hockey, so maybe he would have pushed himself that hard anyway. But it's tough to say).
Third, the consensus on HOH seems to be that Crosby is already somewhere in the range of 5th to 10th place all-time. If Crosby didn't miss any time in those years (and we assume nothing else changes afterwards), he might have become the consensus #5 player of all-time. But is there really a big gap between having him ranked, say, 7th or 8th on average, and being ranked 5th? Give Pierre Turgeon an extra 5% (65 games) - 30 games in 2000, 20 games in 1998, 10 games in 1994, and 5 games whenever - and he'd suddenly have an Art Ross trophy (2000), probably at least a Hart finalist for that year, four top-five scoring finishes, and he'd be over 1,400 points. So he might only gain one trophy (versus six for Crosby), but I'd argue that those extra games would make Turgeon jump 50-100 spots on most people's rankings (and almost certainly get him into the Hall of Fame). So, defined narrowly, Crosby's trophy case is hurt the most, but other players (like Turgeon) would jump the ranks to a much larger extent.