Arturo Gatti
Virgil Hill
Myung-Woo Yuh
Wesley Ramey
Jeff Smith
Joe Coburn
Mills Lane
Jimmy Lennon Jr.
Colin Hart [journalist]
Arturo “Cuyo” Hernandez [manager]
Ted Carroll [cartoonist]
Gatti and Hill were in several career-contemporary sets.
Smith was in some 1920s sets including the 1925 Exhibit issue:
Coburn was in some 19th century issues and also T220.
I don't know of any cards of Ramey or Yuh.
Of the non-participants, the best item I can find for Ted Carroll is this book:
I know Lane is in one of the 1991 sets.