I think on the British scene there a few that have gone missing.
Tony Quigley former British champion beats Dodson loses a close one to Paul Smith only other early career loss is a 6th round stoppage by Nathan Cleverly, gets injured and disappears, comes back with a lacklustre draw against a journeyman after injury and weight problems with the intention of fighting in prizefighter, never seen again, last I heard was working the doors in North Wales.
Joe Selkirk, out of the famous Rotunda amateur boxing club the same crop that produced all the Smith brothers, Tony Bellew and Rocky Fielding. He was said to be the best of the lot by the head trainer there. Turned pro with Warren had a few hand problems and switches of trainers, has fought just 9 times in 4 years and has some okish scalps at LMW. 10th fight is on the Price card against an as of yet unnamed opponent should be at least at British title level now but doesnt look to be going anywhere fast.
Brett Flournoy. Came to the pro game late having been an ABA champion. started to gain some momentum at welter knocked out Yassine El Maachi and was beating McIntyre until the bout was declared a NC because Jason Rushton collapsed entered PF at the weight above beat Danny Butler and Steve O'Meara and lost in the final to Arron after being bundled down in the final. Was a classy boxer with a great shoulder roll who never fought again got into the criminal underworld and was murdered sadly.
Thats just Merseyside.....