The NFL Draft was cut to its current seven round system in 1994. But there were times back in the 1950s and 1960s when the Draft went on for 20, or sometimes, 30 rounds.
In that time there were very few draft picks who were taken in the later rounds that were successful.
I have found a select few players who were later-round picks in drafts with 10 or more rounds. Nine were players and one is a legendary coach and announcer. All of whom, made the Pro Football Hall of Fame.
Players like Tom Brady, Shannon Sharpe and Deacon Jones just go to show that you don't have to be a first round pick to be successful.