Jeff van Note - van Note was one of the best Centers in the league for many years but again played for some lousy teams so he was overlooked.
There are a lot of other deserving players spread out among other teams, but I only included players who have at least one Super Bowl ring. Also, teams like the Vikings who were close many times ought to have a lot of 5-time Pro Bowlers who will never get into the hall.
I think Chuck Howley is the most glaring omission of all. Six-time All Pro, one Super Bowl MVP, and helped hold the Dolphins to 3 points in another Super Bowl. That's the definition of consistency over a long period of time, along with greatness in big games that the voters seem to look for in a player. In most cases.