This is a tough question, but I can list my #1 guy without hesitation, Kerry Collins! He had the arm and accuracy like no other, and that may have also been true in the NFL. He was best when he had good pass protection, and like any other QB, struggled when rushed.
After Collins, the other 4 that come to mind are:
2. Todd Blackledge
3. Chuck Fusina
4. Trace McSorley
5. Michael Robinson
There are so many others that had great careers such as Matt McGloin, John Huffnagle, Chuck Burkhardt, Wally Richardson, Tony Sacca, Daryll Clark and even Christian Hackenburg had a pretty good season under Bill O'Brien.
After Collins, the other 4 that come to mind are:
2. Todd Blackledge
3. Chuck Fusina
4. Trace McSorley
5. Michael Robinson
There are so many others that had great careers such as Matt McGloin, John Huffnagle, Chuck Burkhardt, Wally Richardson, Tony Sacca, Daryll Clark and even Christian Hackenburg had a pretty good season under Bill O'Brien.