Who are the most impressive GateKeepers throughout professional boxing history?

A gatekeeper is a skillful and well-regarded fighter, but one who does not have the popularity or brilliance of a title contender. They are considered to be a cut above most journeymen. A gatekeeper will often have an impressive record in terms of wins versus losses but will have a difficult time getting people behind them and especially obtaining promotion. They are often seen as a "stepping-stone" for potential title contenders to prove their worth against. Yesterday Vladimir Hernandez displayed why he isn't a fighter that should be undermined despite his record of (15-6, 7 KOs) specifically for any upcoming prospect. If a fighter is lacking in any area at the top level he is the type of fighter who will make you pay for it. https://x.com/HotBoxingMinute/status/1798589992199205234? Very impressive that the current light middleweight WBA champion Israil Madrimov managed to beat him in his debut bout in 2018. Someone who went to beat contenders like Aaron Coley (16-2-1), Alfredo Angulo (26-7), Julian Williams (27-2), and Lorenzo Simpson (14-0). Personally I thought he won his bout against Top Rank's middleweight contender Troy Isley (10-0) though I wouldn't say it was a robbery. There are fighters such as Emanuel Augustus whose eccentric style was too flamboyant for the judges despite it's effectiveness thus his record doesn't display how good his skills was. Others are quite physically impressive enough and have a good set of skills that they are able to contend at the top level but lacked the elite skills to attain or retain a title for long. Such as someone like Michael Katsidis, Egidijus Kavaliauskas, Alfredo Angulo or a Orlando Salido.