To dominate at a position, a player needs to have physical ability, intelligence and technique. Obviously, the importance of each of these traits varies by position. Still, these are the crucial factors in determining the most dominant players at each position.
Production is also obviously crucial. But to be dominant means to take over, to be unstoppable. There are elite players who don't fit this bill, but the following athletes are all dominant and seem unbreakable at times.
Some single-handedly win football games.
Disclaimer: Fullbacks were excluded off this list. With the decline in usage of fullbacks and how they are often used interchangeably with running backs or tight ends (H-Backs), they aren't featured enough to be considered dominant.