Name a Boxers who were successful fighting in a square stance ?

Tyson. Dempsey.

Iron Mike

winky, chocolatito, subriel matias is pretty good at it (truly believe he bought his own hype last fight but will be back) golovkin and canelo pretty much fought all 3 fightd squared up

The greatest in-fighters utilized a squared stance like Henry Armstrong, Jake Lamotta, Roberto Duran, Joe Frazier, Mike Tyson, Evander Holyfield, Julio Cesar Chavez Sr, Manny Pacquiao and Chocolatito Gonzalez. Square stance is for the offense heavy. Pros: It helps you throw more punches and combos quicker it gives you more torque on your rotation, so powerful hooks, straights, jabs and uppercuts. Easier to move more effectively with lateral movements and -Can pivot off the left or right foot, so you can move to a better angle. Easier time ring cutting. They also need an active head/waist movement to slip punches since they can't pull out of range like fighters with angled stance who can evade more effectively and also need an active static high guard to block or parry. There is a few examples like Isaac Cruz, Stanionis, Mbilli, and Benavidez as of today. With Canelo being on the downslide.

David Benavidez has some success out of a square stance.

they say canelo tank & winky like a bit of a square dance, i mean stance