12. Tim Tebow (2007)
There have been many great college football players in recent years, but perhaps none of them have been as famous — for many reasons — as Tim Tebow. The three-time All-American, two-time SEC Player of the Year and two-time BCS national champion won the Heisman Trophy in 2007. However, many NFL scouts believed he would be a very poor fit at quarterback at the professional level, and that Tebow would have to change positions to enjoy a long pro career. Spurning that idea, Tebow tried his hand at quarterback in the NFL, with very limited success. While he did lead the Denver Broncos to a playoff win in his second season (2011), by 2012, he was out of the league. There was a brief moment where he was signed by the Philadelphia Eagles in 2015 in training camp, but he never made the team’s final roster.