Pre 60s "alphabet" HW champs with unrecognized claims?

Given the overflow of world titles available the past 60 years it got me wondering about past "alphabet champs". Fighters who were recognized as world champ by the IBU, a national or a state athlethic commission but whose claim wasn't taken seriously and is forgotten today. I am particuarly honed in on "gap" periods where a)the champ wasn't actively defending their belt or b)immediately following the undisputed champs retirement. In both cases it would make sense for organizations to name alternative champs.

Particular periods of interest

Willards inactivity during the late 1910s
Dempseys inactivity during the 1920s
Braddocks inactivity during the 1930s
Titles given out following the retirements of Tunney,Louis(1st one) and Marciano.


Examples that I already have

Peter Jackson
Jake Kilrain
Tom Sharkey
Joe Goddard
Young Stribling
Jack Sharkey(before his universally recognized title)
George Godfrey
Jimmy Bivins(the "duration" title)
Lee Savold
Archie Moore

Boxer recs title filter doesn't seem to be that helpful in this regard(though it does good job showing how many fights were schueduled for the "championship distance").

Am looking for HW world title fights recognized by commissions not state titles recognized by the same organizations or regional titles.