Nice idea; I'll play:
1937 Louis-Braddock newspaper door hanger for newstands:
1963 Cassius Clay reply letter and publicity photo:
Jack Dempsey-Lou Gehrig McGovern's Gym premium:
Louis-Schmeling betting slip:

7.5" x 9.5" [10" x 12" mount] mounted photo of Jim Jeffries on his farm in Burbank with his pup, with a handwritten copyright of 1906 By Jas. J. Jeffries and Jas. M. Johnson [perhaps the photographer], captioned "The Good Friends" in pencil on the mount. From his estate by way of the Helms Sports Museum.
A spectacular Max Baer 8 x 10, inscribed and signed on 8/25/1934, during his one-year reign as heavyweight champion.
A pair of 1920s Cuban matchbox panels of Kid Chocolate

Pac-Man signing a glove for me:
Riddick Bowe signing a ticket for me:
1935 Brown & Bigelow Louis Premium:
Signed contract for 1951 Topps Ringside, from the Topps Archive, Ray Miller, Ruby Goldstein, Barney Ross:
Uncut sheet of 1940s Coney Island Arcade cards (world's weirdest selection--George Courtney???):