It's probably not the best, but I'd just like to mention Bob Sanders in 2007 as one of the best seasons I've seen in some time. He was a tiny guy, but he was unreal against the run. He knew where each play was going, filled the gaps and made TFLs even when coming from the deep safety spot. He'd fly around in coverage and make plays. Teams were afraid to throw over the middle because he'd murder their WRs. His coaches had to keep him out of contact drills in practice because he'd injure his teammates. He played the game at a different speed than everyone else. The difference he made on that Colts defense when he was healthy compared to when he was injured (which was basically all the time) was insane. He completely changed the team. If he was more durable, I think he'd be a HoFer.