It is hard to call any free-agent quarterback a premier free agent, as that is usually a misnomer. There are some exceptions, such as when Peyton Manning became a free agent back in 2012. Of course, Manning will some day have his bust in the Hall of Fame.
This NFL free agency, Dallas Cowboys QB Tony Romo would headline all free agent QBs.
Romo will be the top dog among FA QBs. However, until then you have a lot of QBs that do very little to excite a fan base. Thus, we bring you the closest QB with intrigue in one Mike Glennon.
Glennon displayed some promise with the Tampa Bay Buccaneers before eventually riding the bench behind first-round QB Jameis Winston. In his first season, Glennon threw for 2,608 with 19 touchdowns and nine interceptions with a passer rating of 83.9.
Statistical data provided courtesy of Pro Football Reference.