I have a few that come to mind. Gary Sheffield, agree with Kenny Lofton. Albert Belle - that's a close one, because he came on quick. People will stack his WAR, but in a 12 year career and a 40.1 WAR. To Compare, Mookie Bets has similar award lines in 10 years and is at 64.6 while playing GG defense.
Let me describe to you, a scronny kid that burst onto the scene, took a floundering franchise by storm and brought them back to relevancy. Who would later be traded in the prime of his career to another team where he would finish his career where he would get bigger and stronger with each year and be a perinnial all-star and in the MVP conversation. Who might you ask is that? Miggy Cabrera? Could be Jeff Bagwell but he's already in the hall of fame. It's Barry Bonds. It is an utter travesty that he is not in the HOF!
No fan was complaining that HRs were at an all-time high and bringing fans back to the game. Then pitchers were getting mad because of the tape measure shots and "fair play". Then they banned steroids and started testing - cool. If you get pinched again AFTER the fact - like A-Rod - sure, you knew it was illegal and still did it. BUT if it ceased after the rule went into affect, you can't be held for the past.
Cut to 10 years later, offense is down and now pitchers are making the ball move in ways that no one has ever seen. Enter sticky fingers. Pitchers using sticky substances to enhance grip on the ball to create more spin and more erratic movement and hitters were scared for safety. So, by using the same logic everyone uses for steroid users, anyone caught using sticky stuff whether it be before or after the rule shouldn't get in the hall either, right? Gaylord Perry still got in the HOF by using a pitch that wasn't illegal until it was.