I'm going to bend the rules a bit, since this game was not an official All-Star Game; in fact, it took place over 20 years before the first actual game. And I'm not singling out a particular player, but the game itself. But this game had most of the elements of an All-Star Game, and it took place in Cleveland to boot.
Addie Joss, Cleveland's star pitcher, died suddenly just as the 1911 season was getting started. Joss was admired by teammates and rival players alike, and when he died, his club cancelled their game in Detroit (risking a strike) in order to attend his funeral in Toledo. Afterwards, the club decided to organize a benefit game to help out his wife and children, and players around the league volunteered to come play in it. A mid-season date was selected, and top players from the five clubs who weren't playing arrived in Cleveland to play the Naps at League Park.
The AL team featured seven future Hall of Famers, including Walter Johnson, Ty Cobb, Eddie Collins, Tris Speaker, and Frank "Home Run" Baker. The Naps' lineup didn't have quite the star power, but Cy Young was the starting pitcher, "Shoeless Joe" Jackson was in the outfield, and Nap Lajoie made an appearance. Cobb's uniform got lost on the way to Cleveland, so he was photographed in a Cleveland uniform.
The AL stars would win the game, but the real winners were Joss's family; the proceeds for the game totalled $12,914.00, a massive sum in those days.