I collect the HOF...The International Boxing Hall of Fame. Not an easy collection to complete as the earliest fighters in the HOF predate the actual creation of cards by about 100 years. I too try for career-issued items over items issued in tribute or ATG type sets. My earliest career-contemporary piece is this one:
A copper plate etching from 1824 of HOFer Dick Curtis. Looks pretty good for nearly 200 years old.
And from the Class of 2021:
i am roughly 6-10 fighters away from completion (depends on whether you count female inductees and inductees who were fighters but inducted as referees, trainers or other categories). I suspect some will never be found as cards and I will have to go with a photo.